libaudiohal: Properly notify standby state to HAL

Fix the standby state enforcement for output streams.
Also, bypass reading from FMQ on input when no data
is available.

Bug: 206738075
Test: atest audiorecord_tests
Test: atest trackplayerbase_tests

Change-Id: I53d5b1e81a64547c4179950e804058a3ed9f5871
Signed-off-by: Jasmine Cha <chajasmine@google.com>