Fixed compilation time measurement, restructure some code.

runtime/vm/opt_code_generator_ia32.cc

Index: runtime/vm/opt_code_generator_ia32.cc
===================================================================
--- runtime/vm/opt_code_generator_ia32.cc	(revision 7417)
+++ runtime/vm/opt_code_generator_ia32.cc	(working copy)
@@ -241,7 +241,7 @@
     Assembler* assembler, const ParsedFunction& parsed_function)
         : CodeGenerator(assembler, parsed_function),
           deoptimization_blobs_(4),
-          classes_for_locals_(new ClassesForLocals()),
+          classes_for_locals_(NULL),
           smi_class_(Class::ZoneHandle(Isolate::Current()->object_store()
               ->smi_class())),
           double_class_(Class::ZoneHandle(Isolate::Current()->object_store()
@@ -252,6 +252,12 @@
 }
 
 
+void OptimizingCodeGenerator::InitGenerator() {
+  CodeGenerator::InitGenerator();
+  classes_for_locals_ = new ClassesForLocals();
+}
+
+
 DeoptimizationBlob*
 OptimizingCodeGenerator::AddDeoptimizationBlob(AstNode* node,
                                                DeoptReasonId reason_id) {