Merging r370204:

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r370204 | hans | 2019-08-28 15:55:10 +0200 (Wed, 28 Aug 2019) | 6 lines

[SelectionDAG] Don't generate libcalls for wide shifts on Windows (PR42711)

Neither libgcc or compiler-rt are usually used on Windows, so these
functions can't be called.

Differential revision: https://reviews.llvm.org/D66880
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llvm-svn: 370205