Windows-Clang: Support duplicate object names in LTO archives

Update the archive rules added by commit 6e3655db2c (Clang: add LTO
support for GNU-command line clang on windows, 2019-07-08,
v3.16.0-rc1~161^2~3) to match the `ar` convention we use for normal
archives.

Issue: #21988
1 file changed