RenderWriter checks number of bands before inserting AudioBuffer.
RenderWriter checks number of bands before inserting AudioBuffer.

Temporary work-around for bug webrtc:8759.

Bug: webrtc:8759
Change-Id: Ia830c7e19d7bb332d760f52d62757a443761dc3e
Reviewed-on: https://webrtc-review.googlesource.com/39920
Reviewed-by: Per Åhgren <3616c2c8a2c30a769c5419f89b4a810ea6e2f079@webrtc.org>
Commit-Queue: Gustaf Ullberg <3619ad972adf2eeb42172b0d9b4d612d59d226c7@webrtc.org>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#21639}
TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc