Use both displayName and name in forwardRef/memo (#29625)

When defining a displayName on forwardRef/memo we forward that name to
the inner function.

We used to use displayName for this but in #29206 I switched this to use
`"name"`. That's because V8 doesn't use displayName, it only uses the
overridden name in stack traces. This is the only thing covered by our
tests for component stacks.

However, I realized that Safari only uses displayName and not the name.
So this sets both.

packages/react/src/ReactForwardRef.js

@@ -71,6 +71,7 @@ export function forwardRef<Props, ElementType: React$ElementType>(
           Object.defineProperty(render, 'name', {
             value: name,
           });
+          render.displayName = name;
         }
       },
     });

packages/react/src/ReactMemo.js

@@ -51,6 +51,7 @@ export function memo<Props>(
           Object.defineProperty(type, 'name', {
             value: name,
           });
+          type.displayName = name;
         }
       },
     });