unit test coretest::num::test_i32f64 fails on some targets (again)

[japaric]

I'm seeing #36518 again in smoke. Same test but different affected targets and error message.

Affected targets:

• mips-unknown-linux-gnu
• mips64-unknown-linux-gnuabi64
• mips64el-unknown-linux-gnuabi64
• mipsel-unknown-linux-gnu

Note that the mips64 targets are new-ish and that the 32-bit mips targets are "old" but weren't affected by #36518.

Error message:

---- num::test_i32f64 stdout ----

	thread 'num::test_i32f64' panicked at 'assertion failed: `(left == right)` (left: `2147483647`, right: `-2147483648`)', /rust/lib/rustlib/src/rust/src/libcoretest/num/mod.rs:162

cc @brson @pnkfelix

[steveklabnik]

Triage: not sure what the status of this bug is.

[Dylan-DPC]

Closing this to clear up the issue tracker, and this test is likely fixed already