Restore __ANDROID_API__ guards for core <android/*> APIs

This commit restores the __ANDROID_API__ guards removed in
"Add __INTRODUCED_IN to core <android/*.h> APIs.",
commit 9db409b0.

Add a guard to surface_texture.h.

In choreographer.h, declare the types even for older APIs.

Bug: http://b/111668906
Bug: http://b/113052379
Test: builds
Change-Id: Ia013f48a109310f9f8ca6a3211f28fcb69dd602d
(cherry picked from commit 92b1ebea)