### What this PR does / why we need it?
Pre-construct a mask matrix to improve the efficiency of attention mask
construction during inference.
Note that the length of the matrix needs to be carefully balanced: a
matrix that is too large will consume excessive VRAM, while a matrix
that is too small will require dynamic concatenation during inference,
leading to performance degradation.
Therefore, an environment variable is added here to dynamically set the
size of the pre-constructed mask matrix based on requirements.
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Signed-off-by: shen-shanshan <467638484@qq.com>
Co-authored-by: didongli182 <didongli@huawei.com>
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