Fix TestLoadUnload.test_load_unload for android API > 21

* Change Module::MatchesModuleSpec to return true in case the file spec
  in the specified module spec matches with the platform file spec, but
  not with the local file spec
* Change the module_resolver used when resolving a remote shared module
  to always set the platform file spec to the file spec requested

Differential revision: http://reviews.llvm.org/D12601

llvm-svn: 246852