Merge changes I0c6604ef,Id7e13b3d,I7291d9bd,Ic7c0a2e7,Ic7ce0fd9, ... into main

Merge changes I0c6604ef,Id7e13b3d,I7291d9bd,Ic7c0a2e7,Ic7ce0fd9, ... into main

* changes:
  x86: normalize type with _mm_cvtsi128_si32
  vp9_filter_block_plane_non420: fix implicit conversion warnings
  variance_avx2.c: fix implicit conversion warnings
  vp8,read_mb_modes_mv: fix implicit conversion warnings
  vp8_find_near_mvs: fix implicit conversion warnings
  encode_test_driver: normalize frame_flags type
  vp9,decoder_decode: fix ubsan null/zero offset warning
  y4m_input_fetch_frame: fix ubsan null/zero offset warning