MB: Move Linux GCC to main waterfall.
MB: Move Linux GCC to main waterfall.

Update the name of the trybot as well.

BUG=webrtc:7853
NOTRY=True
TBR=ehmaldonado@webrtc.org

Change-Id: I296ee78b0a61b5a335e3bb794cbec72d85c15970
Reviewed-on: https://chromium-review.googlesource.com/547955
Reviewed-by: Henrik Kjellander <60c11d3e646624f25a02b88f51d51ca6b7ff7c72@webrtc.org>
Commit-Queue: Henrik Kjellander <60c11d3e646624f25a02b88f51d51ca6b7ff7c72@webrtc.org>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#18751}
TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,TimothyGu/libilbc