[patch] Skip async-shell.exp if displaced stepping is not supported

[Tom Tromey]

>>>>> "Yao" == Yao Qi <yao@codesourcery.com> writes:

Yao> 2011-07-13  Yao Qi  <yao@codesourcery.com>
Yao> 	gdb/testsuite/
Yao> 	* gdb.base/async-shell.exp: Skip test if displaced stepping is not
Yao>         supported.

Ok.

Tom