Make atomic ccache replacement work on Windows

Make atomic ccache replacement work on Windows

Commit 371f09d4bf4ca0c7ba15c5ef909bc35307ed9cc3 relies on POSIX
rename() semantics for atomic ccache replacement.  Windows rename()
fails if the destination file exists.  Add a fallback to ReplaceFile()
when this happens.  We may be able to do better using
FILE_RENAME_FLAG_POSIX_SEMANTICS (added in Windows 10 update 1067) but
this should generally suffice.

[ghudson@mit.edu: simplified code slightly; rewrote commit message]

ticket: 9190 (new)
tags: pullup
target_version: 1.22-next