Allow unknown flags in test_main.cc.
Allow unknown flags in test_main.cc.

Adds AllowCommandLineParsing to allow us to ignore "--no-sandbox" given
by new TSanV2 bots. Not ignoring this flag prevents the test from
running on this machine. Also removing unnecessary asserts that clutter
code.

BUG=
TEST=Locally running video_engine_tests with --no-sandbox.
R=stefan@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/2178004

git-svn-id: 03ae4fbe531b1eefc9d815f31e49022782c42458@4679 4adac7df-926f-26a2-2b94-8c16560cd09d

geekboxzone/lollipop_external_chromium_org_third_party_webrtc,android-ia/platform_external_chromium_org_third_party_webrtc,MIPS/external-chromium_org-third_party-webrtc,MIPS/external-chromium_org-third_party-webrtc,Omegaphora/external_chromium_org_third_party_webrtc,android-ia/platform_external_chromium_org_third_party_webrtc,android-ia/platform_external_chromium_org_third_party_webrtc,Omegaphora/external_chromium_org_third_party_webrtc,Omegaphora/external_chromium_org_third_party_webrtc,android-ia/platform_external_chromium_org_third_party_webrtc,Omegaphora/external_chromium_org_third_party_webrtc,MIPS/external-chromium_org-third_party-webrtc,android-ia/platform_external_chromium_org_third_party_webrtc,MIPS/external-chromium_org-third_party-webrtc,MIPS/external-chromium_org-third_party-webrtc,android-ia/platform_external_chromium_org_third_party_webrtc,jgcaaprom/android_external_chromium_org_third_party_webrtc,jgcaaprom/android_external_chromium_org_third_party_webrtc,jgcaaprom/android_external_chromium_org_third_party_webrtc,MIPS/external-chromium_org-third_party-webrtc,Omegaphora/external_chromium_org_third_party_webrtc,android-ia/platform_external_chromium_org_third_party_webrtc,Omegaphora/external_chromium_org_third_party_webrtc,geekboxzone/lollipop_external_chromium_org_third_party_webrtc,android-ia/platform_external_chromium_org_third_party_webrtc,geekboxzone/lollipop_external_chromium_org_third_party_webrtc,jgcaaprom/android_external_chromium_org_third_party_webrtc,jgcaaprom/android_external_chromium_org_third_party_webrtc,geekboxzone/lollipop_external_chromium_org_third_party_webrtc,geekboxzone/lollipop_external_chromium_org_third_party_webrtc,geekboxzone/lollipop_external_chromium_org_third_party_webrtc,geekboxzone/lollipop_external_chromium_org_third_party_webrtc,MIPS/external-chromium_org-third_party-webrtc,geekboxzone/lollipop_external_chromium_org_third_party_webrtc,Omegaphora/external_chromium_org_third_party_webrtc,jgcaaprom/android_external_chromium_org_third_party_webrtc,jgcaaprom/android_external_chromium_org_third_party_webrtc,MIPS/external-chromium_org-third_party-webrtc,jgcaaprom/android_external_chromium_org_third_party_webrtc,Omegaphora/external_chromium_org_third_party_webrtc