Merging r373275:

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r373275 | tstellar | 2019-09-30 16:42:17 -0700 (Mon, 30 Sep 2019) | 9 lines

Fix Driver/modules.cpp test to work when build directory name contains '.s'

Reviewers: dyung, rsmith, hansw

Subscribers: mati865, mgorny, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D66176
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llvm-svn: 374605