Fix a bug in compilation of try-finally.

Fix a bug in compilation of try-finally.

When nesting try-finally, the outer finally was incorrectly executed
twice under certain conditions (a return in the inner try-block and a outer
finally-block that ends with throw)

This was because finally-code was inlined at return/break/continue statements
and it was associated with the wrong catch-handler when compiling.

This CL tracks indices of try-blocks in the parser so that each inlined
finally block has the correct catch handler index.

BUG=https://code.google.com/p/dart/issues/detail?id=11972
TEST=test/language/throw8_test.dart
R=hausner@google.com

Committed: https://code.google.com/p/dart/source/detail?r=25767

[hausner, 2013-08-05 13:07:46]

LGTM.

[Florian Schneider, 2013-08-05 13:49:54]

Committed patchset #1 manually as r25767 (presubmit successful).