Enable full migration of OMX to Treble.

1. Toggling between Treble and non-Treble OMX will now be controlled by
two properties: "persist.hal.binderization" and
"persist.media.treble_omx". (Before this CL, this was controlled by
"debug.treble_omx".)
- If persist.media.treble_omx is not set, it will assume a default value
of -1.
- If persist.media.treble_omx is -1, persist.hal.binderization will be
used to determine whether OMX will be created as a Treble or non-Treble
service.
- If persist.media.treble_omx is 1, OMX will be created as a Treble
service.
- If persist.media.treble_omx has any other value, OMX will be created
as a non-Treble service.
- persist.media.treble_omx can be changed without rebooting, but it will
only take effect after media.codec and mediaserver processes are killed.

2. Remove all dependencies on non-Treble service. This was not done for
MediaCodec, MediaPlayerService::Client, MediaRecorderClient, stagefright
command, and omx_tests command. OMXClient and media.codec process will
now pick the right version of OMX based on properties mentioned above.
Before this CL, media.codec would always present the non-Treble version
of OMX regardless of the flag.

3. Provide workarounds for some HIDL issues.
- A sequence of nested binder and hwbinder calls require many threads to
handle. (b/35283480) The workaround is to increase the number of threads
in the thread pool of media.codec process.
- android.hidl.base@1.0::IBase::unlinkToDeath takes a strong pointer
instead of a weak pointer. (b/35233970) This causes an infinite
recursion in the destructor of ServiceDeathNotifier in
MediaPlayerService::Client and MediaRecorderClient. The workaround moves
calls to unlinkToDeath() outside of the destructor.

Test: Recorded and played videos with Camera app. Ran stagefright and
omx_tests commands.
Bug: 31399200

Change-Id: Id1940ed982838e10bf10fe8ed5b7bb912a5a2d3a