Reland "[llvm-exegesis] Add thread IDs to subprocess memory names (#84451)"

This reverts commit 1fe9c417.

This relands commit 6bbe8a29.

This was causing build failures on one of the ARMv8 builders. Still not
completely sure why, but relanding it to see if the failure pops up
again. If it does, the plan is to fix forward by disabling tests on ARM
temporarily as llvm-exegesis does not currently use SubprocessMemory
on ARM.