coverage-reports keeps failing on Windows (error mentions clear_expected_if_blessed)

[RalfJung]

At least 2 PRs are seeing this error

 ---- [run-make] src/test\run-make\coverage-reports stdout ----

error: make failed
status: exit code: 2
command: "make"
--- stdout -------------------------------
make[1]: Entering directory '/d/a/rust/rust/src/test/run-make/coverage-reports'
make[1]: Leaving directory '/d/a/rust/rust/src/test/run-make/coverage-reports'
------------------------------------------
--- stderr -------------------------------
Makefile:83: clear_expected_if_blessed: No such file or directory
------------------------------------------

Cc #104449 #105160

[RalfJung]

Also see Zulip discussion

[ehuss]

I believe this is now fixed via #105477.