ModGC

Remove references to dead store elimination #2623

Job	Run time
check (default, macos-latest)	7m 18s
check (default, ubuntu-latest)	8m 35s
check (mmtk, release, ubuntu-latest)	11m 26s
check (mmtk, release, macos-latest)	12m 13s
	39m 32s

Provide feedback