* Added tesnorizeation for avx2 based gemm.

Summary:
Tensorized the same region as avx512. Names produce 16x1 int32 results.
Does by doing two sets of AVX2 instructions to do reduction on 8x4 int8
kernel with 1x4 data.

Test Plan:
on avx2 machine:
python tests/python/contrib/test_gemm_avx2_acc32.py

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* Fix lint errors. Removed commented out code.

Summary:

Test Plan:

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