Speedup with ClojureScript printing negative 0 as -0

negative-zero.txt

After adding

(zero? obj) (if (neg? (/ obj)) "-0" "0")

to the number? cond in pr-writer-impl, negative 0 prints as -0, and these
are the associated speedup benchmarks:

                 true     10  ##NaN  ##Inf ##-Inf (js-obj)    -0      0
            V8:  1.03   1.02   1.04   1.02   1.00    1.06   1.06   1.07
  SpiderMonkey:  0.99   1.00   1.01   1.02   1.02    1.08   1.04   1.01
JavaScriptCore:  1.03   1.01   0.79   0.99   1.01    1.00   0.94   0.93
       Nashorn:  1.00   0.90   1.00   1.07   1.05    0.98   1.10   1.23 
    ChakraCore:  1.00   0.97   0.96   0.97   0.97    0.97   1.00   1.02
    

Before:

Benchmarking with V8
;; printing of numbers and handling of ##Nan, ##Inf, ##-Inf
[x true], (pr-str x), 1000000 runs, 393 msecs
[x 10], (pr-str x), 1000000 runs, 576 msecs
[x js/NaN], (pr-str x), 1000000 runs, 660 msecs
[x js/Infinity], (pr-str x), 1000000 runs, 637 msecs
[x js/-Infinity], (pr-str x), 1000000 runs, 591 msecs
[x (js-obj)], (pr-str x), 1000000 runs, 923 msecs
[x (/ js/-Infinity)], (pr-str x), 1000000 runs, 471 msecs
[x (/ js/Infinity)], (pr-str x), 1000000 runs, 560 msecs

Benchmarking with SpiderMonkey
;; printing of numbers and handling of ##Nan, ##Inf, ##-Inf
[x true], (pr-str x), 1000000 runs, 1344 msecs
[x 10], (pr-str x), 1000000 runs, 1293 msecs
[x js/NaN], (pr-str x), 1000000 runs, 1307 msecs
[x js/Infinity], (pr-str x), 1000000 runs, 1318 msecs
[x js/-Infinity], (pr-str x), 1000000 runs, 1352 msecs
[x (js-obj)], (pr-str x), 1000000 runs, 2301 msecs
[x (/ js/-Infinity)], (pr-str x), 1000000 runs, 1315 msecs
[x (/ js/Infinity)], (pr-str x), 1000000 runs, 1315 msecs

Benchmarking with JavaScriptCore
;; printing of numbers and handling of ##Nan, ##Inf, ##-Inf
[x true], (pr-str x), 1000000 runs, 513 msecs
[x 10], (pr-str x), 1000000 runs, 510 msecs
[x js/NaN], (pr-str x), 1000000 runs, 648 msecs
[x js/Infinity], (pr-str x), 1000000 runs, 695 msecs
[x js/-Infinity], (pr-str x), 1000000 runs, 716 msecs
[x (js-obj)], (pr-str x), 1000000 runs, 1213 msecs
[x (/ js/-Infinity)], (pr-str x), 1000000 runs, 791 msecs
[x (/ js/Infinity)], (pr-str x), 1000000 runs, 567 msecs

Benchmarking with Nashorn
;; printing of numbers and handling of ##Nan, ##Inf, ##-Inf
[x true], (pr-str x), 1000000 runs, 1653 msecs
[x 10], (pr-str x), 1000000 runs, 1309 msecs
[x js/NaN], (pr-str x), 1000000 runs, 1273 msecs
[x js/Infinity], (pr-str x), 1000000 runs, 1300 msecs
[x js/-Infinity], (pr-str x), 1000000 runs, 1254 msecs
[x (js-obj)], (pr-str x), 1000000 runs, 2959 msecs
[x (/ js/-Infinity)], (pr-str x), 1000000 runs, 1327 msecs
[x (/ js/Infinity)], (pr-str x), 1000000 runs, 1420 msecs

Benchmarking with ChakraCore
;; printing of numbers and handling of ##Nan, ##Inf, ##-Inf
[x true], (pr-str x), 1000000 runs, 1254 msecs
[x 10], (pr-str x), 1000000 runs, 1149 msecs
[x js/NaN], (pr-str x), 1000000 runs, 1082 msecs
[x js/Infinity], (pr-str x), 1000000 runs, 1096 msecs
[x js/-Infinity], (pr-str x), 1000000 runs, 1091 msecs
[x (js-obj)], (pr-str x), 1000000 runs, 2429 msecs
[x (/ js/-Infinity)], (pr-str x), 1000000 runs, 1143 msecs
[x (/ js/Infinity)], (pr-str x), 1000000 runs, 1156 msecs


After:

Benchmarking with V8
;; printing of numbers and handling of ##Nan, ##Inf, ##-Inf
[x true], (pr-str x), 1000000 runs, 380 msecs
[x 10], (pr-str x), 1000000 runs, 560 msecs
[x js/NaN], (pr-str x), 1000000 runs, 636 msecs
[x js/Infinity], (pr-str x), 1000000 runs, 624 msecs
[x js/-Infinity], (pr-str x), 1000000 runs, 593 msecs
[x (js-obj)], (pr-str x), 1000000 runs, 870 msecs
[x (/ js/-Infinity)], (pr-str x), 1000000 runs, 443 msecs
[x (/ js/Infinity)], (pr-str x), 1000000 runs, 522 msecs

Benchmarking with SpiderMonkey
;; printing of numbers and handling of ##Nan, ##Inf, ##-Inf
[x true], (pr-str x), 1000000 runs, 1352 msecs
[x 10], (pr-str x), 1000000 runs, 1291 msecs
[x js/NaN], (pr-str x), 1000000 runs, 1297 msecs
[x js/Infinity], (pr-str x), 1000000 runs, 1296 msecs
[x js/-Infinity], (pr-str x), 1000000 runs, 1328 msecs
[x (js-obj)], (pr-str x), 1000000 runs, 2132 msecs
[x (/ js/-Infinity)], (pr-str x), 1000000 runs, 1270 msecs
[x (/ js/Infinity)], (pr-str x), 1000000 runs, 1301 msecs

Benchmarking with JavaScriptCore
;; printing of numbers and handling of ##Nan, ##Inf, ##-Inf
[x true], (pr-str x), 1000000 runs, 499 msecs
[x 10], (pr-str x), 1000000 runs, 503 msecs
[x js/NaN], (pr-str x), 1000000 runs, 646 msecs
[x js/Infinity], (pr-str x), 1000000 runs, 700 msecs
[x js/-Infinity], (pr-str x), 1000000 runs, 708 msecs
[x (js-obj)], (pr-str x), 1000000 runs, 1212 msecs
[x (/ js/-Infinity)], (pr-str x), 1000000 runs, 840 msecs
[x (/ js/Infinity)], (pr-str x), 1000000 runs, 607 msecs

Benchmarking with Nashorn
;; printing of numbers and handling of ##Nan, ##Inf, ##-Inf
[x true], (pr-str x), 1000000 runs, 1648 msecs
[x 10], (pr-str x), 1000000 runs, 1460 msecs
[x js/NaN], (pr-str x), 1000000 runs, 1279 msecs
[x js/Infinity], (pr-str x), 1000000 runs, 1216 msecs
[x js/-Infinity], (pr-str x), 1000000 runs, 1191 msecs
[x (js-obj)], (pr-str x), 1000000 runs, 3025 msecs
[x (/ js/-Infinity)], (pr-str x), 1000000 runs, 1203 msecs
[x (/ js/Infinity)], (pr-str x), 1000000 runs, 1159 msecs

Benchmarking with ChakraCore
;; printing of numbers and handling of ##Nan, ##Inf, ##-Inf
[x true], (pr-str x), 1000000 runs, 1259 msecs
[x 10], (pr-str x), 1000000 runs, 1189 msecs
[x js/NaN], (pr-str x), 1000000 runs, 1124 msecs
[x js/Infinity], (pr-str x), 1000000 runs, 1135 msecs
[x js/-Infinity], (pr-str x), 1000000 runs, 1121 msecs
[x (js-obj)], (pr-str x), 1000000 runs, 2511 msecs
[x (/ js/-Infinity)], (pr-str x), 1000000 runs, 1141 msecs
[x (/ js/Infinity)], (pr-str x), 1000000 runs, 1136 msecs