Blessing rmake.rs tests silently does nothing #129038
Description
While working on #129037, I noticed that running an rmake.rs test with --bless appears to succeed, but doesn't actually update the snapshot file(s).
This seems to be a side-effect of #126097. The test does successfully bless the temporary copy of the snapshot file in build/, but that has no effect on the original snapshot file in tests/run-make/.