Implement testbench for comprehensive testing

[jserv]

mung, another L4.X2 compatible microkernel, has a nice testbench, which deploys at least the following test items:

• forkserv: service that takes over the root task's memory, letting it fork subprocesses (and subprocesses of those). this is useful for test cases involving map operations in IPC, or the Unmap system call.
• interrupt: tests about interrupt handling per the L4.X2 spec. heavily tied to PC-style x86 due to serial port use.
• ipc: tests concerning the Ipc system call, with the exception of anything related to string transfers.
• scheduler: kernel preemption
• thread: unit tests concerning the ThreadControl and ExchangeRegister system calls, and TCR access.
• type: tests wrt the types defined by <l4/types.h>

We can port parts of the test suite and evaluate on F9 Microkernel.

[jserv]

Related: #11

[jserv]

After the evaluation, we plan to take the benchmark suite from L4Ka::Pistachio instead of the one from mung for initial target.