Merging r338703 and r338709:

Merging r338703 and r338709:

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r338703 | bd1976llvm | 2018-08-02 13:27:38 +0200 (Thu, 02 Aug 2018) | 8 lines

[llvm-ar] Correct help text

Corrected and simplified the help text.

It was clearly too difficult to maintain before (see e.g. @227296) making it
simpler and more consistent it should help people keep it up to date.

Differential Revision: https://reviews.llvm.org/D48577
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r338709 | bd1976llvm | 2018-08-02 14:27:01 +0200 (Thu, 02 Aug 2018) | 3 lines

[llvm-ar] Fix help text test. NFC.

Missed from @338703
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_70@338840 91177308-0d34-0410-b5e6-96231b3b80d8