Fix non stopping breakpoint on newer compilers.

Fix non stopping breakpoint on newer compilers.

The breakpoint presented in the return statement was not activated while
compiling the test with gcc 4.9.2.  Added a dummy statement to allow the
breakpoint again.

2015-10-14  Walfred Tedeschi  <walfred.tedeschi@intel.com>

gdb/testsuite:

	* i386-mpx-map.c (foo): Add dummy statement to trigger breakpoint.

Change-Id: I5293ca1c7f82a631e1e41cb650c30dd2d09ef3c2
Signed-off-by: Walfred Tedeschi <walfred.tedeschi@intel.com>