PlatformDarwinKernel was treating its file path arg as a kext bundle id -- but when the user
did a manual "target modules add", it would be a file path.  If the kext bundle lookup fails,
fall back to calling PlatformDarwin's GetSharedModule which will handle a file path correctly.
<rdar://problem/14179858> 


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@184237 91177308-0d34-0410-b5e6-96231b3b80d8