Merging r354957:

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r354957 | ibiryukov | 2019-02-27 11:16:03 +0100 (Wed, 27 Feb 2019) | 11 lines

[clangd] Set thread priority on Windows

Reviewers: kadircet, gribozavr

Reviewed By: kadircet, gribozavr

Subscribers: ioeric, MaskRay, jkorous, arphaman, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D58683
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llvm-svn: 354984