[ARM64] Disable regression tests for the old JIT.

Since the ARM64 backend doesn't implement support for the old JIT those tests are failing when the regression tests are run on an AArch64 host.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207530 91177308-0d34-0410-b5e6-96231b3b80d8
LinkModulesTest.cpp: Use test-specific Ctx instead of getGlobalContext(). The global context might not be free'd. [vg_leak]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207535 91177308-0d34-0410-b5e6-96231b3b80d8
[CMake] Enable llvm/unittests/LinkerTests. It had not been enabled since r199354.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207536 91177308-0d34-0410-b5e6-96231b3b80d8
LinkModulesTest.cpp: Reformat.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207537 91177308-0d34-0410-b5e6-96231b3b80d8