fix(slider): Guard against unnecessary touch events in IE as they are unnecessary

Author: pgbross

packages/mdc-slider/continuous/foundation.js

@@ -106,7 +106,9 @@ export default class MDCSliderFoundation extends MDCFoundation {
   }
 
   handleTouchMove_(event) {
-    if (event.pointerType && event.pointerType !== 'touch') {
+    // IE processes events on the input[range] without additional help
+    // unlike Safari iOS.
+    if (this.isIE_ || (event.pointerType && event.pointerType !== 'touch')) {
       return;
     }