Add -exec-abort command (MI); Don't exit on eStateExited
Summary:
Add -exec-abort command + test.
Also, I had fixed an error, when lldb-mi exits on eStateExited. With current patch we can re-run target:
```
-file-exec-and-symbols hello
^done
-exec-run
^running
*stopped,reason="breakpoint-hit"...
-exec-abort
^done
*stopped,reason="exited-normally"... <- program exits
-exec-run <- run again
^running
*stopped,reason="breakpoint-hit"...
```
All tests pass on OS X.
Reviewers: zturner, emaste, abidh, clayborg
Reviewed By: abidh, clayborg
Subscribers: lldb-commits, emaste, zturner, clayborg, abidh
Differential Revision: http://reviews.llvm.org/D7794
llvm-svn: 230321