Disable JITLoaderGDB on "vendor == apple" for now due to performance slowdowns for every first run process as a global name lookup in all shared libraries if performed.

<rdar://problem/16542894>

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@205734 91177308-0d34-0410-b5e6-96231b3b80d8