Merging r338841:

Merging r338841:
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r338841 | jmorse | 2018-08-03 12:13:35 +0200 (Fri, 03 Aug 2018) | 11 lines

[Windows FS] Allow moving files in TempFile::keep

In r338216 / D49860 TempFile::keep was extended to allow keeping across
filesystems. The aim on Windows was to have this happen in rename_internal
using the existing system API. However, to fix an issue and preserve the
idea of "renaming" not being a move, put Windows keep-across-filesystem in
TempFile::keep.

Differential Revision: https://reviews.llvm.org/D50048

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_70@340030 91177308-0d34-0410-b5e6-96231b3b80d8