Add a check for null thread before trying to suspend

The patch fixes a jpda test failure due to a failed
assertion in SuspendThreadByThreadId. There should be
a check for a null thread before the assertion check.
This was the behavior of previous code (4.4.2) where
this test passes, but this check was removed during
some refactoring of the code.

Change-Id: Ia63de5f159ce1e51110bf9dc604011d07b2f048e
Signed-off-by: Johnnie Birch <johnnie.l.birch.jr@intel.com>
1 file changed