Rollup merge of #145405 - durin42:test-cleanup-tmpdir, r=lqd

cleanup: use run_in_tmpdir in run-make/rustdoc-scrape-examples-paths

We had an issue on our LLVM-head Rust builder where it got stuck with this test failing because it was reusing the tmpdir between runs and something broke the incremental compile. Everything seems to work fine with run_in_tmpdir in this test. tests/run-make/uefi-qemu also uses the same tmpdir across runs, but I don't have the right environment to test that so I didn't try fixing it. That is the only use of std::env::temp_dir left in run-make tests after this fix.

Author: Zalathar