Merging r279980:

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r279980 | david.majnemer | 2016-08-29 10:14:08 -0700 (Mon, 29 Aug 2016) | 7 lines

[SimplifyCFG] Hoisting invalidates metadata

We forgot to remove optimization metadata when performing hosting during
FoldTwoEntryPHINode.

This fixes PR29163.

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llvm-svn: 288063