Enable conservative mode in GC, verify all is good about llilc HOT 3 CLOSED

@swaroop-sridhar can you take this one? Make sure we coordinate and get this into test scripts and automation.

from llilc.

To verify that Conservative GC works for LLILC Jitted code, I ran a test code that allocates a lot of memory and calls GC.Collect() continuously in a loop.

I checked that

1. The memory allocation and GC.Collect() methods are JITted by LLILCJit.
2. If Conservative GC is not enabled, the CoreCLR crashes trying to walk the stack, as expected
3. If Conservative GC is enabled, the program runs to completion.
4. TaskMgr shows several rounds of allocation and collection.

I think this is sufficient evidence that Conservative GC is working on LLILC Jit, and we should enable it in the testing framework.

If using a Debug build of CoreCLR, I got some Assert() failures in CoreCLR. These failures did not abort execution – the program still ran to completion.
At least some of the failures seem to occur because LLILC run leaks lot more memory than the CoreCLR runtime likes to tolerate. I'll open a separate work item for this and investigate.

from llilc.

ConservativeGC mode is enabled in the testing framework, so this task is now complete.

from llilc.