Added voice_engine_unittests and voe_auto_test targets to GN.
Added voice_engine_unittests and voe_auto_test targets to GN.

I didn't convert the APK tests, since I couldn't figure it out, nor
find any that had already been converted to copy from. I might get to it
in a new CL or even second patch-set.

BUG=webrtc:6039

Review-Url: https://codereview.webrtc.org/2123243003
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#13410}

TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc