remove unnecessary flush buffer in encoder
to support cross-platform UT of lD/ST 32 in scroll detection
Prevent misaligned warning in UT
remove multiplication overflow warning by ULL instead of LL
Rollup of Gecko Media Plugin patches
Merge pull request #981 from ethanhugg/gmp_rollup

Rollup of Gecko Media Plugin patches
Merge pull request #980 from huili2/enc_remove_bsflush

remove unnecessary flush buffer in encoder
Merge pull request #976 from huili2/modify_EncUT_scroll_xplatform

to support cross-platform LD32 in scroll detection
Merge pull request #978 from huili2/ULL_insteadof_LL

remove multiplication overflow warning by ULL instead of LL
Merge pull request #979 from huili2/modify_DecUT_intra

Prevent misaligned warning in UT