l4test: mark unimplemented test functions
user: remove unused files
user: remove boot information since F9 has different processes
user: drop obsolete x86 definitions and revise ARM specific
platform: Disable bitmap bit-band because as userspace workaround

At present, there is no enough space for generating bitmap in bit-band
regions when larger userspace is introduced.
user: bench: drop unused pingpong since we plan to write newer one
user: drop unused grabmem because we don't have sigma0
user: drop sigma0
l4test: declare the proper architecture