Merging r327099:

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r327099 | rsmith | 2018-03-08 18:00:01 -0800 (Thu, 08 Mar 2018) | 3 lines

PR36645: Go looking for an appropriate array bound when constant-evaluating a
name of an array object.

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git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_60@329478 91177308-0d34-0410-b5e6-96231b3b80d8