tests/gem_reset_stats: fix length check in inject_hang
tests/gem_reset_stats: fix length check in inject_hang

To avoid writing past the batch end.

Signed-off-by: Mika Kuoppala <cd221c71e765d1ce593d15b204fee351fb09fd98@intel.com>

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