[analyzer] Handle caching out while evaluating a C++ new expression.

Evaluating a C++ new expression now includes generating an intermediate
ExplodedNode, and this node could very well represent a previously-
reachable state in the ExplodedGraph. If so, we can short-circuit the
rest of the evaluation.

Caught by the assertion a few lines later.

<rdar://problem/13510065>

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@178401 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Analysis/new.cpp b/test/Analysis/new.cpp
index 004a05e..44ae980 100644
--- a/test/Analysis/new.cpp
+++ b/test/Analysis/new.cpp
@@ -94,6 +94,14 @@
   new (p) (int *)(static_cast<int *>(malloc(4))); // no-warning
 }
 
+void testCacheOut(PtrWrapper w) {
+  extern bool coin();
+  if (coin())
+    w.x = 0;
+  new (&w.x) (int*)(0); // we cache out here; don't crash
+}
+
+
 //--------------------------------------------------------------------
 // Check for intersection with other checkers from MallocChecker.cpp 
 // bounded with unix.Malloc