Merging r323935:

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r323935 | rsmith | 2018-02-01 01:28:36 +0100 (Thu, 01 Feb 2018) | 5 lines

PR36181: Teach CodeGen to properly ignore requests to emit dependent entities.

Previously, friend function definitions within class templates slipped through
the gaps and caused the MS mangler to assert.

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git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_60@324215 91177308-0d34-0410-b5e6-96231b3b80d8