strace: Introduce FlagsTypeHandler, and use it for O_* modes.

Change-Id: I1569084a71c32834c0ff3d8dc71ef3de9d5a817d
Reviewed-on: https://review.haiku-os.org/c/haiku/+/6263
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>
Tested-by: Automation <automation@haiku-os.org>

strace: trace fcntl and wait_for_child syscalls parameters

Change-Id: I774e8343139a2bdb3c2f60f37cab3a7207739c7c
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5251
Reviewed-by: waddlesplash <waddlesplash@gmail.com>
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>