[lldb] Fix bug in fallback logic for finding the resource directory.

[JDevlieghere]

Summary

Both of the if-clauses modify the raw_path variable and the SharedFrameworks variant wasn't properly resetting the variable. Avoid future bugs like that by always resetting the variable.

[teemperor]

LGTM

lldb/source/Plugins/ExpressionParser/Clang/ClangHost.cpp

if (*parent == "System") {
       //       "My.xctoolchain/System/Library/PrivateFrameworks/LLDB.framework"
       raw_path.resize(parent - r_end);
       llvm::sys::path::append(clang_path, raw_path, swift_clang_resource_dir);
       if (!verify || VerifyClangPath(clang_path)) {
         file_spec.GetDirectory().SetString(clang_path.c_str());
         FileSystem::Instance().Resolve(file_spec);
         return true;
       }
-      raw_path = lldb_shlib_spec.GetPath();
     }
-    raw_path.resize(rev_it - r_end);
-  } else {
-    raw_path.resize(rev_it - r_end);
   }
 
   // Fall back to the Clang resource directory inside the framework.
+  raw_path = lldb_shlib_spec.GetPath();
+  raw_path.resize(rev_it - r_end);
   raw_path.append("LLDB.framework/Resources/Clang");
   file_spec.GetDirectory().SetString(raw_path.c_str());
   FileSystem::Instance().Resolve(file_spec);
   return true;
 #endif // __APPLE__
 }
 
 FileSpec lldb_private::GetClangResourceDir() {