Merging r367008:

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r367008 | stulova | 2019-07-25 13:04:29 +0200 (Thu, 25 Jul 2019) | 12 lines

[OpenCL] Rename lang mode flag for C++ mode

Rename lang mode flag to -cl-std=clc++/-cl-std=CLC++
or -std=clc++/-std=CLC++.

This aligns with OpenCL C conversion and removes ambiguity
with OpenCL C++. 

Differential Revision: https://reviews.llvm.org/D65102



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llvm-svn: 367300