Rename SurfaceMediaSource::dump to dumpState

A method named dump() is already exported by Binder.  The warnings
were hidden by the use of -isystem to include frameworks/av/include.

Bug: 31751828
Test: m -j checkbuild
Change-Id: If460a6efc7c7b108243c3ef068c28619482f599d
(cherry picked from commit f461f38e)