Allow fchmod syscalls on code-coverage builds

Bug: http://b/177693725

fchmod is used to ensure profraw files are readable by all users with
Clang's profile merging.

Test: ensure mediaswcodec doesn't crash in code coverage build.
Change-Id: Ia1e3b5b51c1d2fc86d548cfd066e849b03004731
5 files changed