VM: Remove dead code from flow graph optimizer.

runtime/vm/compiler.cc

Index: runtime/vm/compiler.cc
diff --git a/runtime/vm/compiler.cc b/runtime/vm/compiler.cc
index d5ceba554976cfda899536d8aff672df60e173dc..4c707a0de2c6582c7ee33f83bf3fe239cf40f861 100644
--- a/runtime/vm/compiler.cc
+++ b/runtime/vm/compiler.cc
@@ -25,6 +25,7 @@
 #include "vm/flow_graph_compiler.h"
 #include "vm/flow_graph_inliner.h"
 #include "vm/flow_graph_optimizer.h"
+#include "vm/flow_graph_range_analysis.h"
 #include "vm/flow_graph_type_propagator.h"
 #include "vm/il_printer.h"
 #include "vm/longjump.h"
@@ -885,7 +886,8 @@ bool CompileParsedFunctionHelper::Compile(CompilationPipeline* pipeline) {
           // We have to perform range analysis after LICM because it
           // optimistically moves CheckSmi through phis into loop preheaders
           // making some phis smi.
-          optimizer.InferIntRanges();
+          RangeAnalysis range_analysis(flow_graph);
+          range_analysis.Analyze();
           DEBUG_ASSERT(flow_graph->VerifyUseLists());
         }