fix(cdk/text-field): Long multiline textfield focus issue.

When we have long multiline textfield and put cursor on almost an end (For eg. on 3rd last line) the scroll moves up to the top of textarea. This fix will use `blur` and `focus` in `scrollToCaretPosition` method

Fixes angular#20255

src/cdk/text-field/autosize.ts

@@ -367,6 +367,8 @@ export class CdkTextareaAutosize implements AfterViewInit, DoCheck, OnDestroy {
     // it to receive focus on IE and Edge.
     if (!this._destroyed.isStopped && this._hasFocus) {
       textarea.setSelectionRange(selectionStart, selectionEnd);
+      textarea.blur();
+      textarea.focus();
     }
   }
 }