intel-gpu-tools: Move igt tests to intel validation area

intel-gpu-tools: Move igt tests to intel validation area

Currently when IGT is built for Android the resulting test
executables go to /system/bin, which is not ideal. After
discussion with the core validation team i have moved them
to /system/vendor/intel/validation/core/igt by setting
LOCAL_MODULE_PATH.

I have also added a --defsym linker option to export a
symbol that allows a script to easily distinguish between
tests that have subtests and those that dont. There are
better ways to do this (viz, in the source code) but
because the igt tests are not written consistently this
would require many more changes.

Signed-off-by: Tim Gore <tim.gore@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>