[turbofan] Change RawMachineAssembler to take a CallDescriptor instead of a MachineSi...

[turbofan] Change RawMachineAssembler to take a CallDescriptor instead of a MachineSignature.

The InterpreterAssembler needs to specify a specific CallDescriptor type
instead of using the SimplifiedCDescriptor type. This CL makes it possible
to specify the CallDescriptor used by the RawMachineAssembler instead of
specifying a MachineSignature.

Also removes instruction-selector-tester.h which was erroneously resurrected
at some point.

BUG=v8:4280
LOG=N

Review URL: https://codereview.chromium.org/1235313002

Cr-Commit-Position: refs/heads/master@{#29777}