clang-tidy: fix readability-redundant-member-init lints

vtkm/cont/ArrayHandle.h

@@ -154,10 +154,7 @@ struct GetTypeInParentheses<void(T)>
   VTKM_IS_ARRAY_HANDLE(Superclass);                                                                \
                                                                                                    \
   VTKM_CONT                                                                                        \
-  classname()                                                                                      \
-    : Superclass()                                                                                 \
-  {                                                                                                \
-  }                                                                                                \
+  classname() {}                                                                                   \
                                                                                                    \
   VTKM_CONT                                                                                        \
   classname(const Thisclass& src)                                                                  \

vtkm/exec/FunctorBase.h

@@ -31,10 +31,7 @@ class VTKM_ALWAYS_EXPORT FunctorBase
 {
 public:
   VTKM_EXEC_CONT
-  FunctorBase()
-    : ErrorMessage()
-  {
-  }
+  FunctorBase() {}
 
   VTKM_EXEC
   void RaiseError(const char* message) const { this->ErrorMessage.RaiseError(message); }