libgui: Add frame number and clean up BQ dump

Adds the frame counter and the frame numbers of each buffer in the
BufferQueue to its dumpState. Also cleans up both the formatting of the
dumpState source and its output.

Bug: 38178182
Test: Manual testing with `dumpsys SurfaceFlinger`
Change-Id: Id3869a796e59ab00b26c3eb9cd958a9179bc8b7e