Merging r339597:

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r339597 | erichkeane | 2018-08-13 20:33:20 +0200 (Mon, 13 Aug 2018) | 7 lines

Enforce instantiation of template multiversion functions

Multiversioned member functions inside of a template type were 
not properly being emitted.  The solution to this is to simply 
ensure that their bodies are correctly evaluated/assigned during
template instantiation.

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git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_70@339663 91177308-0d34-0410-b5e6-96231b3b80d8