Reduced dont-infinite-loop-during-block-escape-analysis.ll with bugpoint and moved it to retain-block-escape-analysis.ll.

*NOTE* I verified that the original bug behind
dont-infinite-loop-during-block-escape-analysis.ll occurs when using opt on
retain-block-escape-analysis.ll.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177240 91177308-0d34-0410-b5e6-96231b3b80d8