[Orc] Honor hasJIT in JITTargetMachineBuilder::createTargetMachine

Even with D129349 <https://reviews.llvm.org/D129349>, various SPARC JIT
tests still `FAIL`.  They are guarded by `host-supports-jit`.  This is set
from `clang-repl --host-supports-jit` which still returns `true`.  It turns
out the `JITTargetMachineBuilder` doesn't consider `hasJIT` at all.

This patch corrects this, turning the affected tests `UNSUPPORTED`.

Tested on `sparcv9-sun-solaris2.11`.

Differential Revision: https://reviews.llvm.org/D129350