`test/run-make-fulldeps/pgo-branch-weights` fails occasionally on CI

[JohnTitor]

You can see this test fails occasionally in some pull requests: https://github.com/rust-lang/rust/pulls?utf8=%E2%9C%93&q=is%3Apr+pgo-branch-weights

I don't think this is due to PR changes. Could we modify, or just remove this for now?

[Centril]

cc @Zoxc @michaelwoerister

[michaelwoerister]

If the test fails, it indicates that there's a bug to be fixed. I'll try to reproduce.

[pnkfelix]

triage: P-high, removing nomination