Remove code supporting incremental compilation in dart2js

pkg/compiler/lib/src/js_emitter/code_emitter_task.dart

Index: pkg/compiler/lib/src/js_emitter/code_emitter_task.dart
diff --git a/pkg/compiler/lib/src/js_emitter/code_emitter_task.dart b/pkg/compiler/lib/src/js_emitter/code_emitter_task.dart
index 879f29fc96f8bf6832192b405c11d371ba661d41..430f1de3caf2941bd0c1257d331b5c453beb1a3c 100644
--- a/pkg/compiler/lib/src/js_emitter/code_emitter_task.dart
+++ b/pkg/compiler/lib/src/js_emitter/code_emitter_task.dart
@@ -174,8 +174,6 @@ class CodeEmitterTask extends CompilerTask {
 
   int assembleProgram(Namer namer, ClosedWorld closedWorld) {
     return measure(() {
-      emitter.invalidateCaches();
-
       Set<ClassEntity> rtiNeededClasses = _finalizeRti();
       ProgramBuilder programBuilder = new ProgramBuilder(
           compiler, namer, this, emitter, closedWorld, rtiNeededClasses);
@@ -250,6 +248,4 @@ abstract class Emitter {
 
   /// Returns the size of the code generated for a given output [unit].
   int generatedSize(OutputUnit unit);
-
-  void invalidateCaches();
 }