Add test case for type with partial parameterization by method type parameter

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

Index: pkg/compiler/lib/src/ssa/builder.dart
diff --git a/pkg/compiler/lib/src/ssa/builder.dart b/pkg/compiler/lib/src/ssa/builder.dart
index 77025b0cc96e44c2c2224bc462b7a3d62b9d76ad..0be1efb8b9824332d66467b58b758971319c9de0 100644
--- a/pkg/compiler/lib/src/ssa/builder.dart
+++ b/pkg/compiler/lib/src/ssa/builder.dart
@@ -4753,6 +4753,9 @@ class SsaBuilder extends ast.Visitor
   HInstruction addTypeVariableReference(TypeVariableType type,
       {SourceInformation sourceInformation}) {
     assert(assertTypeInContext(type));
+    if (type is MethodTypeVariableType) {
+      return graph.addConstantNull(compiler);
+    }

[eernst, 2016/08/22 14:58:50]

This looked a bit surprising at first, but it ended up being resolved as
follows:

I actually had the following in this method for a similar purpose, inserted at
line 4804:

   } else if (type is MethodTypeVariableType) {
     // TODO(eernst): The enclosing `else if` was added to provide minimal
     // support for generic methods: The method type arguments are always
     // pretending to have the value `dynamic`. Revise for full support.
     DynamicType type = const DynamicType();
     JavaScriptBackend backend = compiler.backend;
     ClassElement cls = backend.helpers.DynamicRuntimeType;
     HInstruction instruction =
         new HDynamicType(type, new TypeMask.exact(cls, compiler.world));
     add(instruction);
     return instruction;

This was reviewed by Johnni Winther and it worked for a while. It was removed
again because it wasn't executed by any test case after other changes had been
made. But I believe that you have just fixed this by adding a suitable test (so
it wasn't impossible to reach it after all).

The remaining issue is that I generated code to return an `HDynamicType` whereas
this CL generates code to yield null.

Looking at `analyzeTypeArgument`, `inlineSuperOrRedirect`, and other locations,
I've confirmed that the above approach is used to provide a runtime value for
`dynamic`.

In the end, I have no worries about this!

     Element member = sourceElement;
     bool isClosure = member.enclosingElement.isClosure;
     if (isClosure) {