Candidate fix for "Missing serialize function for REPR ContextRef"

Locally.pm.diff

diff --git a/src/core/CompUnit/Repository/Locally.pm b/src/core/CompUnit/Repository/Locally.pm
index bab6b34..5a8d6f1 100644
--- a/src/core/CompUnit/Repository/Locally.pm
+++ b/src/core/CompUnit/Repository/Locally.pm
@@ -9,8 +9,12 @@ role CompUnit::Repository::Locally {
         my $abspath := $*SPEC.rel2abs($prefix);
         my $IO      := IO::Path.new-from-absolute-path($abspath);
 
+        nqp::scwbdisable();
         %instances{$abspath} //=
           self.bless(:prefix($IO), :lock(Lock.new), :WHICH(self.^name ~ '|' ~ $abspath), :$next-repo);
+        nqp::scwbenable();
+
+        %instances{$abspath};
     }
 
     multi method Str(CompUnit::Repository::Locally:D:) { $!prefix.abspath }