[PATCH] Add invoke statepoint placement tests

[Philip Reames]

LGTM with comment addressed.

p.s. Can you add one test for the single entry phi issue?  This can be a separate change if that's easier.


REPOSITORY
  rL LLVM

================
Comment at: test/Transforms/PlaceSafepoints/invokes.ll:3
@@ +2,3 @@
+
+; ModuleID = '<stdin>'
+
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Remove this please.

http://reviews.llvm.org/D7535

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