Reproduction steps:
1. Open the "WebGL Audio.zip" project
2. Build the only scene on WebGL build
3. Press any key from 1-8 to play sounds
-Observe that sounds are not playing

Note: Pressing keys from A to K (QWERTY) calls AudioSource.PlayClipAtPoint which plays sounds as expected.
Note: After calling AudioSource.PlayClipAtPoint audio clip becomes playable from AudioSource component, except for Streaming audio files

Actual result: No sounds are played
Expected result: Sounds are played from AudioSource component

Reproduced on: 5.6.0a3, 5.5.0f1, 5.4.2p3
Not reproducible on: 5.3.7p1, 5.3.6p7