camera2: Make legacy error handling more robust.

- Relax internal timeout for JPEG captures in LEGACY mode.
- Make RequestThreadManager.quit() idempotent to avoid queuing
  messages on a dead thread's handler.
- Catch RuntimeExceptions from other Camera1 API methods to
  allow proper cleanup + release of Camera1 API client.

Bug: 19255187
Change-Id: I6cb08bb6b832b0d0df6ee6e8983c35de2df4a408