Remove support for 'argument definitions test' from dart2js.

sdk/lib/_internal/compiler/implementation/js_backend/constant_emitter.dart

Index: sdk/lib/_internal/compiler/implementation/js_backend/constant_emitter.dart
diff --git a/sdk/lib/_internal/compiler/implementation/js_backend/constant_emitter.dart b/sdk/lib/_internal/compiler/implementation/js_backend/constant_emitter.dart
index c3cff04c73932dca47aed52636e49f0918d23956..ace154a497833dbe25791671a28824c10e9681d5 100644
--- a/sdk/lib/_internal/compiler/implementation/js_backend/constant_emitter.dart
+++ b/sdk/lib/_internal/compiler/implementation/js_backend/constant_emitter.dart
@@ -61,10 +61,6 @@ class ConstantReferenceEmitter implements ConstantVisitor<jsAst.Expression> {
     return constant.accept(this);
   }
 
-  jsAst.Expression visitSentinel(SentinelConstant constant) {
-    return new jsAst.VariableUse(namer.CURRENT_ISOLATE);
-  }
-
   jsAst.Expression visitFunction(FunctionConstant constant) {
     return new jsAst.VariableUse(
         namer.isolateStaticClosureAccess(constant.element));
@@ -173,11 +169,6 @@ class ConstantInitializerEmitter implements ConstantVisitor<jsAst.Expression> {
     return referenceEmitter.generateInInitializationContext(constant);
   }
 
-  jsAst.Expression visitSentinel(SentinelConstant constant) {
-    compiler.internalError(
-        "The parameter sentinel constant does not need specific JS code");
-  }
-
   jsAst.Expression visitFunction(FunctionConstant constant) {
     compiler.internalError(
         "The function constant does not need specific JS code");