profiling: flush stdout before writing profile to stderr
On py3, stdout and stderr appear to be buffered and this causes my command's
output to be intermixed with the profiling output.
Differential Revision: https://phab.mercurial-scm.org/D8024
rust: re-format with nightly rustfmt
This fixes test-check-rust-format.t.
Differential Revision: https://phab.mercurial-scm.org/D8025
tests: stablize test-rename-merge1.t on Windows
This goes with
d7622fdec3b5.
Differential Revision: https://phab.mercurial-scm.org/D8036