Remove HRuntimeType implementation

pkg/compiler/lib/src/ssa/type_builder.dart

Index: pkg/compiler/lib/src/ssa/type_builder.dart
diff --git a/pkg/compiler/lib/src/ssa/type_builder.dart b/pkg/compiler/lib/src/ssa/type_builder.dart
index 44eb5bce9b40c7475c6665a441a0df8af90d1d8c..5724e107ed2824759d64de5217f5eb9cc80d163e 100644
--- a/pkg/compiler/lib/src/ssa/type_builder.dart
+++ b/pkg/compiler/lib/src/ssa/type_builder.dart
@@ -250,7 +250,12 @@ class TypeBuilder {
       return new HTypeConversion.withTypeRepresentation(
           type, kind, subtype, original, typeVariable);
     } else if (type.isFunctionType) {
-      return builder.buildFunctionTypeConversion(original, type, kind);
+      HInstruction reifiedType =
+          analyzeTypeArgument(type, builder.sourceElement);
+      // TypeMasks don't encode function types.
+      TypeMask refinedMask = original.instructionType;
+      return new HTypeConversion.withTypeRepresentation(
+          type, kind, refinedMask, original, reifiedType);
     } else {
       return original.convertType(builder.closedWorld, type, kind);
     }