Remove redundant string initialization (NFC)

Identified with readability-redundant-string-init.

clang-tools-extra/clangd/refactor/tweaks/ObjCMemberwiseInitializer.cpp

@@ -40,7 +40,7 @@ static std::string getTypeStr(const QualType &OrigT, const Decl &D,
   QualType T = OrigT;
   PrintingPolicy Policy(D.getASTContext().getLangOpts());
   Policy.SuppressStrongLifetime = true;
-  std::string Prefix = "";
+  std::string Prefix;
   // If the nullability is specified via a property attribute, use the shorter
   // `nullable` form for the method parameter.
   if (PropertyAttributes & ObjCPropertyAttribute::kind_nullability) {

mlir/lib/Pass/Pass.cpp

@@ -90,7 +90,7 @@ struct OpPassManagerImpl {
       : name(name == OpPassManager::getAnyOpAnchorName() ? "" : name.str()),
         initializationGeneration(0), nesting(nesting) {}
   OpPassManagerImpl(OpPassManager::Nesting nesting)
-      : name(""), initializationGeneration(0), nesting(nesting) {}
+      : initializationGeneration(0), nesting(nesting) {}
   OpPassManagerImpl(const OpPassManagerImpl &rhs)
       : name(rhs.name), opName(rhs.opName),
         initializationGeneration(rhs.initializationGeneration),