Refactor branch instructions to enable further optimizations.

runtime/vm/intermediate_language.cc

Index: runtime/vm/intermediate_language.cc
===================================================================
--- runtime/vm/intermediate_language.cc	(revision 11450)
+++ runtime/vm/intermediate_language.cc	(working copy)
@@ -1339,6 +1339,17 @@
 }
 
 
+void StrictCompareComp::EmitBranchCode(FlowGraphCompiler* compiler,
+                                       BranchInstr* branch) {
+  Register left = locs()->in(0).reg();
+  Register right = locs()->in(1).reg();
+  ASSERT(kind() == Token::kEQ_STRICT || kind() == Token::kNE_STRICT);
+  Condition true_condition = (kind() == Token::kEQ_STRICT) ? EQUAL : NOT_EQUAL;
+  __ CompareRegisters(left, right);
+  branch->EmitBranchOnCondition(compiler, true_condition);
+}
+
+
 void ClosureCallComp::EmitNativeCode(FlowGraphCompiler* compiler) {
   // The arguments to the stub include the closure.  The arguments
   // descriptor describes the closure's arguments (and so does not include