message: Remove some debug logging from the Splitter
diff: @@ -199,8 +199,6 @@ export class Splitter extends ThemeableElementBase {
  private _handleMouseDown(ev: MouseEvent): void {
  const target = <HTMLElement> ev.target;
  - this._log.debug("target: ", target);
  - this._log.debug("has divider: ", target.classList.contains(CLASS_DIVIDER));
  if ( ! target.classList.contains(CLASS_DIVIDER)) {
  return;
  @@ -225,10 +223,6 @@ export class Splitter extends ThemeableElementBase {
  this._dividerDrag = dividerIndex;
  this._dividerDragOffsetX = ev.offsetX;
  - this._log.debug("this._dividerDrag: ", this._dividerDrag);
  -
  - this._log.debug("ev.offsetX: ", ev.offsetX);
  - this._log.debug("ev.offsetY: ", ev.offsetY);
  const topDiv = DomUtils.getShadowId(this, ID_TOP);
  topDiv.classList.add(CLASS_DRAG);
  @@ -245,8 +239,6 @@ export class Splitter extends ThemeableElementBase {
  }
  const target = <HTMLElement> ev.target;
  - this._log.debug("target: ", target);
  - this._log.debug("has divider: ", target.classList.contains(CLASS_DIVIDER));
  ev.preventDefault();
  ev.stopPropagation();
  @@ -296,7 +288,6 @@ export class Splitter extends ThemeableElementBase {
  }
  private _handleMouseLeave(ev: MouseEvent): void {
  - this._log.debug("_handleMouseLeave",ev.target);
  this._stopDrag();
  }
  