lib/igt_core.c: Flag the test as failing after a segfault
lib/igt_core.c: Flag the test as failing after a segfault

fatal_signal_handler() was trapping fatal errors but not
flagging the test as failing or setting an exit code.
The result was that the test would return Ok or Skipped
depending on what the other subtests did even though one
of the subtests had segfaulted.

Signed-off-by: Derek Morton <6938752c4b6118c105a32254fd77180dc6bea19f@intel.com>
Signed-off-by: Daniel Vetter <c1b6782c4af8f0673da8923a0702a1832e5940f4@ffwll.ch>

mv0/intel-gpu-tools,chenxianqin/intel-gpu-tools,dlespiau/checkmate-test-igt,tiagovignatti/intel-gpu-tools,tiagovignatti/intel-gpu-tools,tiagovignatti/intel-gpu-tools,tiagovignatti/intel-gpu-tools,mv0/intel-gpu-tools,chenxianqin/intel-gpu-tools,dlespiau/checkmate-test-igt,chenxianqin/intel-gpu-tools,chenxianqin/intel-gpu-tools,mv0/intel-gpu-tools,dlespiau/checkmate-test-igt,mv0/intel-gpu-tools,dlespiau/checkmate-test-igt