This is basically same commit as e38e954a0d249f88d0a55504f70d6055e865a931 which was reverted later in 676953fde9120cda62e4ef2f75a804af7481d6af
In both cases, this changes weren't benchmarked.
e38e954a0d249f88d0a55504f70d6055e865a931 leads to missed optimization described in [this issue](https://github.com/rust-lang/rust/issues/62993)
676953fde9120cda62e4ef2f75a804af7481d6af leads to missed optimization described in [this issue](https://github.com/rust-lang/rust/issues/83623)
Also it changes some src/test/run-make-fulldeps/coverage-spanview/expected_mir_dump* files automatically.