test=release/0.15.0

(cherry-pick from commit 478eeabd)

(cherry-pick from commit 3de45566)

Merge pull request from #12843 from NHZlX:fix_ssa_bug_for_trt

Because of the changing trt engine op from gpu to gpu mode.

(cherry-pick from commit 145b20c160329428c1ec05c94287708aa1ed6f63)

cherry-pick from commit 133ec696

(cherry picked from commit 1600ba86)

* hide misc APIs

* update

* fix transformer test

* update API.spec