Fix triggers for ILLINK job (dotnet/coreclr#10244)

Fix triggers for ILLINK job (dotnet/coreclr#10244)

This change has the following fixes:
1) Fix the trigger phrase for ILLink jobs so that PRs can request ILLink runs per architecture.

2) Pass the linker location explicitly on the runtest.cmd command line
instead of using the %ILLink% variable, since the build/run steps
are different command shells.

3) Don't run the x86compatijit configuration daily in the lab

Commit migrated from https://github.com/dotnet/coreclr/commit/65f6120ddd0197076f3cd247f273c213a0a78272