Merging r338968:

Merging r338968:
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r338968 | echristo | 2018-08-05 16:23:37 +0200 (Sun, 05 Aug 2018) | 6 lines

Revert "Add a warning if someone attempts to add extra section flags to sections"

There are a bunch of edge cases and inconsistencies in how we're emitting sections
cause this warning to fire and it needs more work.

This reverts commit r335558.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_70@339099 91177308-0d34-0410-b5e6-96231b3b80d8