[test] [fuzzer] Enable tests for iossim, disable for ios (update2)

The fuzzer tests cross_over.test and merge-control-file.test are not handled
correctly on ios device testing. On-device testing requires the macros %t, %s,
etc. to be expanded for a different default directory than when testing on host.

rdar://99889376

Differential Revision: https://reviews.llvm.org/D133811