Merging r340900:

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r340900 | hans | 2018-08-29 08:55:27 +0200 (Wed, 29 Aug 2018) | 6 lines

LoopSink: Don't sink into blocks without an insertion point (PR38462)

In the PR, LoopSink was trying to sink into a catchswitch block, which
doesn't have a valid insertion point.

Differential Revision: https://reviews.llvm.org/D51307
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_70@341048 91177308-0d34-0410-b5e6-96231b3b80d8