Reproduction Steps:
1. Import attached project.
2. Open "Test" scene.
3. Enter Play mode.
4. Observe console.

Expected result: Console prints out "1".
Actual result: Console prints out "0".

Reproducible with: 5.6.0b5, 5.6.0b10
Not reproducible with: 5.4.3p3, 5.5.2f1, 5.6.0b4
Regression introduced in: 5.6.0b5

Note: The beta still seems to be able to record audio through a microphone. An extra script is attached to record audio.

Reproduction Steps:
1. Select "ScriptTest" in Hierarchy.
2. Enter Play mode.
3. Say something into the microphone.
4. Open the file within the Audio Source parameter AudioClip in Inspector.
5. Listen to the recording.