Merging r339603:

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r339603 | abataev | 2018-08-13 21:04:24 +0200 (Mon, 13 Aug 2018) | 4 lines

[OPENMP] Fix emission of the loop doacross constructs.

The number of loops associated with the OpenMP loop constructs should
not be considered as the number loops to collapse.
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git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_70@339851 91177308-0d34-0410-b5e6-96231b3b80d8