VM: Fix receiver type propagation in presence of try-catch.

tests/language/vm/optimized_try_catch_cha_test.dart

+// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+// VMOptions=--optimization_counter_threshold=100 --no-use-osr --no-background_compilation
+
+// Test CHA-based optimizations in presence of try-catch.
+
+import "package:expect/expect.dart";
+
+bar(i) {
+  if (i == 11) throw 123;
+}
+
+class A {
+  var f = 42;
+  
+  foo(i) {
+    do {
+      try {
+        bar(i);
+      } catch (e, s) {
+        Expect.equals(123, e);
+      }
+    } while (i < 0);
+    return f;
+  }
+}
+
+class B extends A {
+
+}
+
+main() {
+  var result;
+  for (var i = 0; i < 200; i++) {
+    try {
+      result = new B().foo(i);
+    } catch (e) { }
+  }
+  Expect.equals(42, result);
+}