Merging r359569:

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r359569 | russell_gallop | 2019-04-30 08:35:16 -0700 (Tue, 30 Apr 2019) | 7 lines

Add llvm-profdata to LLVM_TOOLCHAIN_TOOLS

This is required for using PGO on Windows but isn't in the Windows
release packages. Windows packages are built with
LLVM_INSTALL_TOOLCHAIN_ONLY so only includes llvm "tools" listed here.

Differential Revision: https://reviews.llvm.org/D61317
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llvm-svn: 360801