Add test where X is defined differentlty in co-importing libraries

Add test where X is defined differentlty in co-importing libraries


*** Replaced by http://codereview.chromium.org/8802018/


AFAIK this should work because the imports use prefixes.

Frog: passes

VM:
'/usr/local/google/home/sra/dart-all/dart/tests/language/src/LibrarySameNameUsedLib2.dart': Error: Class 'X' is used where an interface is expected


Dartc:
tests/language/src/LibrarySameNameUsedLib2.dart/LibrarySameNameUsedLib2.dart:13: no such type "lib2"
    12: 
    13: X makeX() { return new lib2.X(); }
                               ~~~~
tests/language/src/LibrarySameNameUsedLib2.dart/LibrarySameNameUsedLib2.dart:13: New expression does not resolve to a constructor
    12: 
    13: X makeX() { return new lib2.X(); }
                               ~~~~~~

BUG=
TEST=