Several significant improvements to the MMTk debugging Harness.
- Now maintains a 'shadow stack' in the heap, to support collectors that do
deferred tracing of roots.
- The deterministic scheduler yield algorithm no longer changes its behaviour
when watchpoints, tracing etc are enabled.
- Watchpoints can now be enabled on variables in the test scripts
- Scripts can specify harness options, especially heap size. Each plan has
a configured 'heap factor' which is used to scale the specified heap size
to allow for copy reserves etc.
- Short names for plans are now implemented in the harness rather than in the
wrapper script. This simplifies command lines.
- New intrinsic to return the number of GCs that have occurred. The SpreadAlloc
scripts have been updated to perform a certain number of GCs.