Add SearchPathRemapper to SearchPathOptions

This is intended to be used from LLDB to apply the remappings
specified in target.source-map to remap any serialized
Swiftmodule search paths that were prefixed using
`-prefix-serialized-debugging-options`.

lib/Serialization/ModuleFile.cpp

@@ -158,9 +158,11 @@ Status ModuleFile::associateWithFileContext(FileUnit *file, SourceLoc diagLoc,
     return error(status);
   }
 
-  for (const auto &searchPath : Core->SearchPaths)
-    ctx.addSearchPath(searchPath.Path, searchPath.IsFramework,
-                      searchPath.IsSystem);
+  for (const auto &searchPath : Core->SearchPaths) {
+    ctx.addSearchPath(
+        ctx.SearchPathOpts.SearchPathRemapper.remapPath(searchPath.Path),
+        searchPath.IsFramework, searchPath.IsSystem);
+  }
 
   auto clangImporter = static_cast<ClangImporter *>(ctx.getClangModuleLoader());