AArch64: adjust tests which rely on a default JIT

Profiling tests *do* need a JIT. They'll pass if a cross-compiler targetting
AArch64 by default has been built, but fail if a native AArch64 compiler has
been build. Therefore XFAIL is inappropriate and we mark them unsupported.

ExecutionEngine tests are JIT by definition, they should also be unsupported.

Transforms/LICM only uses the interpreter to check the output is still sane
after optimisation. It can be switched to use an interpreter.