igt/gem_ctx_exec: Add lrc lite restore subtest
igt/gem_ctx_exec: Add lrc lite restore subtest

Exercise lite-restore (re-submit a context that is currently running),
by queueing several small batchbuffers.

This test helps to validate WaIdleLiteRestore.

Signed-off-by: Michel Thierry <c65ff7d3dfaea3345301797f027f123ededb124c@intel.com>

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