Add flow types RNTester examples (#22829)

Summary:
This PR adds flow types for the RNTester examples, and updates all of the RNTester examples to match the flow type consistently.

Previously, there was a mix of static class definitions and whether or not pages exported examples or a component. Now we will always export the same way, enforced by flow types

Note: I also fixed most of the $FlowFixMe in changed components
Pull Request resolved: https://github.com/facebook/react-native/pull/22829

Reviewed By: cpojer

Differential Revision: D13563191

Pulled By: rickhanlonii

fbshipit-source-id: b697e3346a863d1b130881592b0522a96c202b63

RNTester/js/AnimatedExample.js

@@ -15,6 +15,22 @@ const ReactNative = require('react-native');
 const {Animated, Easing, StyleSheet, Text, View} = ReactNative;
 const RNTesterButton = require('./RNTesterButton');
 
+const styles = StyleSheet.create({
+  content: {
+    backgroundColor: 'deepskyblue',
+    borderWidth: 1,
+    borderColor: 'dodgerblue',
+    padding: 20,
+    margin: 20,
+    borderRadius: 10,
+    alignItems: 'center',
+  },
+  rotatingImage: {
+    width: 70,
+    height: 70,
+  },
+});
+
 exports.framework = 'React';
 exports.title = 'Animated - Examples';
 exports.description =
@@ -58,11 +74,11 @@ exports.examples = [
           );
         }
       }
-      class FadeInExample extends React.Component<$FlowFixMeProps, any> {
-        /* $FlowFixMe(>=0.85.0 site=react_native_fb) This comment suppresses an
-         * error found when Flow v0.85 was deployed. To see the error, delete
-         * this comment and run Flow. */
-        constructor(props) {
+
+      type Props = $ReadOnly<{||}>;
+      type State = {|show: boolean|};
+      class FadeInExample extends React.Component<Props, State> {
+        constructor(props: Props) {
           super(props);
           this.state = {
             show: true,
@@ -287,19 +303,3 @@ exports.examples = [
     render: () => <Text>Checkout the Gratuitous Animation App!</Text>,
   },
 ];
-
-const styles = StyleSheet.create({
-  content: {
-    backgroundColor: 'deepskyblue',
-    borderWidth: 1,
-    borderColor: 'dodgerblue',
-    padding: 20,
-    margin: 20,
-    borderRadius: 10,
-    alignItems: 'center',
-  },
-  rotatingImage: {
-    width: 70,
-    height: 70,
-  },
-});