chore(*): fix some unit tests

Author: viktorkombov

projects/igniteui-angular/src/lib/grids/grid/column-resizing.spec.ts

@@ -50,7 +50,7 @@ describe('IgxGrid - Deferred Column Resizing #grid', () => {
             headerResArea = GridFunctions.getHeaderResizeArea(headers[0]).nativeElement;
         }));
 
-        it('should define grid with resizable columns.', fakeAsync(() => {
+        fit('should define grid with resizable columns.', fakeAsync(() => {
 
             expect(grid.columns[0].width).toEqual('100px');
             expect(grid.columns[0].resizable).toBeTruthy();

projects/igniteui-angular/src/lib/test-utils/grid-functions.spec.ts

@@ -1875,12 +1875,12 @@ export class GridFunctions {
     }
 
     public static clickHeaderSortIcon(header: DebugElement) {
-        const sortIcon = this.getHeaderSortIcon(header);
+        const sortIcon = header.query(By.css(SORT_ICON_CLASS));
         sortIcon.triggerEventHandler('click', new Event('click'));
     }
 
     public static verifyHeaderSortIndicator(header: DebugElement, sortedAsc = true, sortedDesc = false, sortable = true) {
-        const sortIcon = this.getHeaderSortIcon(header);
+        const sortIcon = header.query(By.css(SORT_ICON_CLASS));
         if (sortable) {
             const sortIconText = sortedDesc ? SORTING_ICON_DESC_CONTENT : SORTING_ICON_ASC_CONTENT;
             expect(sortIcon.nativeElement.textContent.trim()).toEqual(sortIconText);