Implement substitution for type variables.

Implement substitution for type variables.

Committed: https://code.google.com/p/dart/source/detail?r=18376

[karlklose, 2013-02-08 09:31:38]

The main part of this patch has been reviewed as
https://codereview.chromium.org/12018015/.

[karlklose, 2013-02-08 14:51:46]

Nicolas, PTAL at the builder/codegen change wrt.
https://codereview.chromium.org/12210013/

This is not ready for committing, as I am still missing generated substitution
for some native classes  (see html.status).

https://codereview.chromium.org/12218007/diff/11005/sdk/lib/_internal/compile...
File sdk/lib/_internal/compiler/implementation/ssa/builder.dart (right):

https://codereview.chromium.org/12218007/diff/11005/sdk/lib/_internal/compile...
sdk/lib/_internal/compiler/implementation/ssa/builder.dart:2659: void
argumentsCheck() {
@Nicolas: this is the main change to the previous version; I generate a
&&-control-flow here instead of the codegen. This simplifies handling in the
codegen and makes short-cutting work correctly, but the generated code is less
readable because our if-retranslation is not good enough.

[blois, 2013-03-02 01:43:53]

https://codereview.chromium.org/12218007/diff/11005/tests/html/html.status
File tests/html/html.status (right):

https://codereview.chromium.org/12218007/diff/11005/tests/html/html.status#ne...
tests/html/html.status:331: element_test/queryAll: Fail # missing substitution
on native classes
These failures are extremely disturbing- this is core functionality which is now
untested.

I do not think this CL should have been submitted if it breaks these tests-
these are testing very basic functionality.