Android textTransform style support (#20572)

Summary:
Issue facebook/react-native#2088 (closed, but a bit pre-emptively imo, since Android support was skipped)

Related (merged) iOS PR facebook/react-native#18387

Related documentation PR facebook/react-native-website#500

The basic desire is to have a declarative mechanism to transform text content to uppercase or lowercase or titlecase ("capitalized").
Pull Request resolved: facebook/react-native#20572

Differential Revision: D9311716

Pulled By: hramos

fbshipit-source-id: dfbb855117196958e7ae5e980700d31be07a448d

js/TextExample.android.js

@@ -531,6 +531,56 @@ class TextExample extends React.Component<{}> {
             make text look slightly misaligned when centered vertically.
           </Text>
         </RNTesterBlock>
+        <RNTesterBlock title="Text transform">
+          <Text style={{textTransform: 'uppercase'}}>
+            This text should be uppercased.
+          </Text>
+          <Text style={{textTransform: 'lowercase'}}>
+            This TEXT SHOULD be lowercased.
+          </Text>
+          <Text style={{textTransform: 'capitalize'}}>
+            This text should be CAPITALIZED.
+          </Text>
+          <Text style={{textTransform: 'capitalize'}}>
+            Mixed: <Text style={{textTransform: 'uppercase'}}>uppercase </Text>
+            <Text style={{textTransform: 'lowercase'}}>LoWeRcAsE </Text>
+            <Text style={{textTransform: 'capitalize'}}>
+              capitalize each word
+            </Text>
+          </Text>
+          <Text>
+            Should be "ABC":
+            <Text style={{textTransform: 'uppercase'}}>
+              a<Text>b</Text>c
+            </Text>
+          </Text>
+          <Text>
+            Should be "AbC":
+            <Text style={{textTransform: 'uppercase'}}>
+              a<Text style={{textTransform: 'none'}}>b</Text>c
+            </Text>
+          </Text>
+          <Text style={{textTransform: 'none'}}>
+            {
+              '.aa\tbb\t\tcc  dd EE \r\nZZ I like to eat apples. \n中文éé 我喜欢吃苹果。awdawd   '
+            }
+          </Text>
+          <Text style={{textTransform: 'uppercase'}}>
+            {
+              '.aa\tbb\t\tcc  dd EE \r\nZZ I like to eat apples. \n中文éé 我喜欢吃苹果。awdawd   '
+            }
+          </Text>
+          <Text style={{textTransform: 'lowercase'}}>
+            {
+              '.aa\tbb\t\tcc  dd EE \r\nZZ I like to eat apples. \n中文éé 我喜欢吃苹果。awdawd   '
+            }
+          </Text>
+          <Text style={{textTransform: 'capitalize'}}>
+            {
+              '.aa\tbb\t\tcc  dd EE \r\nZZ I like to eat apples. \n中文éé 我喜欢吃苹果。awdawd   '
+            }
+          </Text>
+        </RNTesterBlock>
       </RNTesterPage>
     );
   }