fix(text-input): fix floating labels by getting the value of the ngControl if it exists

Added some test cases for this to the floating labels example. Closes
#710

ionic/components/text-input/test/floating-labels/index.ts

@@ -4,4 +4,12 @@ import {App} from 'ionic/ionic';
 @App({
   templateUrl: 'main.html'
 })
-class E2EApp {}
+class E2EApp {
+  constructor() {
+    this.myValues = {
+      value1: 'Dynamic Input',
+      value2: 'Dynamic Textarea'
+    };
+  }
+
+}

ionic/components/text-input/test/floating-labels/main.html

@@ -8,10 +8,11 @@
 
     <ion-input floating-label>
       <ion-label>Floating Label 1</ion-label>
-      <input type="text">
+      <input [(ng-model)]='myValues.value1' type="text">
     </ion-input>
+    Value: {{ myValues.value1 }}
 
-    <ion-input floating-label class="input-has-value">
+    <ion-input floating-label>
       <ion-label>Floating Label 2</ion-label>
       <input value="Has Value" type="text">
     </ion-input>
@@ -23,8 +24,9 @@
 
     <ion-input floating-label>
       <ion-label primary>Floating Label 4</ion-label>
-      <textarea></textarea>
+      <textarea [(ng-model)]='myValues.value2'></textarea>
     </ion-input>
+    Value: {{ myValues.value2 }}
 
     <ion-input floating-label>
       <ion-label secondary>Floating Label 5</ion-label>