build: disable -Og when building with clang
clang does not yet support -Og, fall back to -O0.
Fixes: https://github.com/iojs/io.js/issues/1608 See: https://llvm.org/bugs/show_bug.cgi?id=20765
R=@Fishrock123?
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
clang does not yet support -Og, fall back to -O0.
Fixes: https://github.com/iojs/io.js/issues/1608 See: https://llvm.org/bugs/show_bug.cgi?id=20765
R=@Fishrock123?