igt/gem_fenced_exec_thrash: Fix memory leak between tests
igt/gem_fenced_exec_thrash: Fix memory leak between tests

gem_fenced_exec_thrash was not freeing any resources between
subtests. On 1Gb android systems this resulted in the test
failing with an OOM error.

Added cleanup code to free BOs at the end of each subtest.

Signed-off-by: Derek Morton <6938752c4b6118c105a32254fd77180dc6bea19f@intel.com>

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