DO NOT MERGE Add "dumpsys SurfaceFlinger --dispsync"

Dumps the current DispSync state.

Bug 14651879

(this is a near-cherrypick of Ide4e6dbd58b117bc1a6b97b57d10cd92ec86dc84)

Change-Id: I6e6c8452ede5c2d5098db1b884d28226e77d9a03
4 files changed