Base webrtc fuzzers on a template.

Removes noisy dependencies on webrtc_fuzzer_main and removal of
find_bad_constructs, removes 1-6 lines of gn per fuzzer target.

BUG=webrtc:4771
R=kjellander@webrtc.org

Review URL: https://codereview.webrtc.org/1524993002 .

Cr-Original-Commit-Position: refs/heads/master@{#11022}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 5ea3da2cbbb0710f9617fb0627c0c4258437b09f
2 files changed