Merging r340191:

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r340191 | abataev | 2018-08-20 20:03:40 +0200 (Mon, 20 Aug 2018) | 6 lines

[OPENMP] Fix crash on the emission of the weak function declaration.

If the function is actually a weak reference, it should not be marked as
deferred definition as this is only a declaration. Patch adds checks for
the definitions if they must be emitted. Otherwise, only declaration is
emitted.
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git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_70@340351 91177308-0d34-0410-b5e6-96231b3b80d8