Add more tests for verifying the behavior of CAudioManager class

Add more tests for verifying the behavior of CAudioManager class

Previously, only a single test was available for CAudioManager class,
which definitely is not an adequate number to verify its behavior.
For this reason, added more tests to verify the current implementation
of CAudioManager class and also to guarantee the future modification
will not cause any unexpected results.

[==========] Running 11 tests from 1 test suite.
[----------] Global test environment set-up.
[----------] 11 tests from DefaultFixture
[ RUN      ] DefaultFixture.StreamsAllDataFed
[       OK ] DefaultFixture.StreamsAllDataFed (1 ms)
[ RUN      ] DefaultFixture.StreamsAllDataFedAfterClear
[       OK ] DefaultFixture.StreamsAllDataFedAfterClear (0 ms)
[ RUN      ] DefaultFixture.OnRecordingAudioDataCallbackProperlyCalled
[       OK ] DefaultFixture.OnRecordingAudioDataCallbackProperlyCalled (1 ms)
[ RUN      ] DefaultFixture.OnRecordingAudioDataCallbackProperlyCalledAfterFinalizing
[       OK ] DefaultFixture.OnRecordingAudioDataCallbackProperlyCalledAfterFinalizing (0 ms)
[ RUN      ] DefaultFixture.RecordingStartsWhenRequestedWithSoundFocus
[       OK ] DefaultFixture.RecordingStartsWhenRequestedWithSoundFocus (0 ms)
[ RUN      ] DefaultFixture.RecordingDoesNotStartWhenRequestedWithSoundFocus
[       OK ] DefaultFixture.RecordingDoesNotStartWhenRequestedWithSoundFocus (0 ms)
[ RUN      ] DefaultFixture.RecordingStopsWhenRequested
[       OK ] DefaultFixture.RecordingStopsWhenRequested (0 ms)
[ RUN      ] DefaultFixture.RecordingStopsWhenSoundFocusLost
[       OK ] DefaultFixture.RecordingStopsWhenSoundFocusLost (0 ms)
[ RUN      ] DefaultFixture.RecordingStartsWhenSoundFocusAcquiredAgain
[       OK ] DefaultFixture.RecordingStartsWhenSoundFocusAcquiredAgain (0 ms)
[ RUN      ] DefaultFixture.RecordingStartsWhenSoundFocusAcquiredLater
[       OK ] DefaultFixture.RecordingStartsWhenSoundFocusAcquiredLater (0 ms)
[ RUN      ] DefaultFixture.RecordingDoesNotStartWhenSoundFocusAcquiredAgainIfStopped
[       OK ] DefaultFixture.RecordingDoesNotStartWhenSoundFocusAcquiredAgainIfStopped (0 ms)
[----------] 11 tests from DefaultFixture (2 ms total)

[----------] Global test environment tear-down
[==========] 11 tests from 1 test suite ran. (2 ms total)
[  PASSED  ] 11 tests.

Change-Id: I50939d259e0b4f1072c6f7e1e2948ea1856eae38