This adds a unit test to show the type checking functionality missing in dartc

This adds a unit test to show the type checking functionality missing  in dartc

This refines omitting the runtime-type checks in certain cases to just apply to
type variables (original disabled by r2660)

BUG=925
TEST=

Committed: https://code.google.com/p/dart/source/detail?r=2771

[zundel, 2011-12-20 21:38:58]

http://codereview.chromium.org/8956047/diff/1/compiler/java/com/google/dart/c...
File compiler/java/com/google/dart/compiler/resolver/ResolverErrorCode.java
(right):

http://codereview.chromium.org/8956047/diff/1/compiler/java/com/google/dart/c...
compiler/java/com/google/dart/compiler/resolver/ResolverErrorCode.java:139:
WRONG_NUMBER_OF_TYPE_ARGUMENTS("%s: wrong number of type arguments.  Expected
%d");
I decided to improve this error message when I ran across it writing the unit
test.

[codefu, 2011-12-22 16:13:50]

lgtm

http://codereview.chromium.org/8956047/diff/4001/tests/language/src/TypeCheck...
File tests/language/src/TypeChecksInFactoryMethodTest.dart (right):

http://codereview.chromium.org/8956047/diff/4001/tests/language/src/TypeCheck...
tests/language/src/TypeChecksInFactoryMethodTest.dart:16: // If T is not a
string, runtime type checks should fail
And instance-of check should also fail.