VoE: revert CHECKs into asserts
VoE: revert CHECKs into asserts

Including check.h causes build failure in Chrome due to LOG macros redefinition.

Review URL: https://webrtc-codereview.appspot.com/51629004

Cr-Original-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#8984}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 6fc2d2f487b3e6223dff518e04fb301ba6d2cf43

Alkalyne/webrtctrunk,jchavanton/webrtc,Alkalyne/webrtctrunk,krieger-od/webrtc,Alkalyne/webrtctrunk,sippet/webrtc,jchavanton/webrtc,jchavanton/webrtc,sippet/webrtc,aleonliao/webrtc-trunk,Alkalyne/webrtctrunk,jchavanton/webrtc,krieger-od/webrtc,aleonliao/webrtc-trunk,jchavanton/webrtc,aleonliao/webrtc-trunk,Alkalyne/webrtctrunk,sippet/webrtc,aleonliao/webrtc-trunk,krieger-od/webrtc,krieger-od/webrtc,sippet/webrtc,Alkalyne/webrtctrunk,aleonliao/webrtc-trunk,krieger-od/webrtc,Alkalyne/webrtctrunk,aleonliao/webrtc-trunk,sippet/webrtc,jchavanton/webrtc,jchavanton/webrtc,krieger-od/webrtc,Alkalyne/webrtctrunk,sippet/webrtc