Rename GCAnonymousSymbols() to GCSymbols() and some cleanup
Remove callsite gc root
Update test cases for verifying reference count
Using RuntimeMemory.PushFrameForGlobals() to extend stack for global variables
Handle the case that expected value is null
GC deactivated symbols
Fix test cases
Fix test cases
Not use freelist in verification mode
Merge pull request #2737 from ke-yu/mark_and_sweep

Mark and sweep - part 3