Remove DebuggerEvent. Refactor remaining code.

runtime/vm/flow_graph_range_analysis_test.cc

Index: runtime/vm/flow_graph_range_analysis_test.cc
diff --git a/runtime/vm/flow_graph_range_analysis_test.cc b/runtime/vm/flow_graph_range_analysis_test.cc
index 8f919430328e0f2a95ce820f90b4e7a6fd314d51..7f89ba17c0e04a291d1daec71e32743716373b30 100644
--- a/runtime/vm/flow_graph_range_analysis_test.cc
+++ b/runtime/vm/flow_graph_range_analysis_test.cc
@@ -76,12 +76,14 @@ TEST_CASE(RangeTests) {
                 RangeBoundary(kMinInt64),
                 RangeBoundary::PositiveInfinity());
   if (kBitsPerWord == 64) {
+#if 0

[turnidge, 2016/05/12 20:06:05]

Ignore this change -- I need it because I am on the most recent xcode.  Will
revert it before I commit.

[turnidge, 2016/05/13 15:49:35]

I fixed the warning I was seeing in the most recent xcode as part of this cl. 
For the record, it was a complaint that shifting a signed negative number is
undefined.

     TEST_RANGE_OP_SMI(Range::Shl, -1, 1, 62, 62,
                   RangeBoundary(kSmiMin),
-                  RangeBoundary(kSmiMax));
+                  RangeBoundary(kSmiMax));
     TEST_RANGE_OP_SMI(Range::Shl, -1, 1, 30, 30,
                   RangeBoundary(-1 << 30),
-                  RangeBoundary(1 << 30));
+                  RangeBoundary(1 << 30));
+#endif
   } else {
     TEST_RANGE_OP_SMI(Range::Shl, -1, 1, 30, 30,
                   RangeBoundary(kSmiMin),