Change string used to annotate static type issues to 'static type warning' in multitest

Change string used to annotate static type issues to 'static type warning' in multitest

Gilad requested we update the annotation used in multitests to reflect
the terminology used in the Dart specification.

Committed: https://code.google.com/p/dart/source/detail?r=5233

[zundel, 2012-03-09 01:18:45]

The static analysis engine is the only implementation that actually does
anything with these annotations at the moment.  I remember discussing this with
Peter at one point.

[Mads Ager (google), 2012-03-09 13:16:05]

lgtm

[Bill Hesse, 2012-03-09 13:57:16]

LGTM.