clang-tidy: Use = default

Suppress some cases in `Source/cmGeneratorExpressionNode.cxx` and
`Source/cmUVHandlePtr.h` where a few older compilers require a
user-defined default constructor (with `{}`).

Source/cmFileCommand.cxx

@@ -1079,7 +1079,7 @@ struct cmFileCopier
     , Doing(DoingNone)
   {
   }
-  virtual ~cmFileCopier() {}
+  virtual ~cmFileCopier() = default;
 
   bool Run(std::vector<std::string> const& args);
 
@@ -1102,7 +1102,7 @@ protected:
   {
     bool Exclude = false;
     mode_t Permissions = 0;
-    MatchProperties() {}
+    MatchProperties() = default;
   };
   struct MatchRule
   {