refactor(material/table): clean up IE workarounds (#23462)

Cleans up the workarounds for IE in the table module.

Author: crisbeto

src/cdk/table/cell.ts

@@ -150,12 +150,7 @@ export class CdkColumnDef extends _CdkColumnDefBase implements CanStick {
 /** Base class for the cells. Adds a CSS classname that identifies the column it renders in. */
 export class BaseCdkCell {
   constructor(columnDef: CdkColumnDef, elementRef: ElementRef) {
-    // If IE 11 is dropped before we switch to setting a single class name, change to multi param
-    // with destructuring.
-    const classList = elementRef.nativeElement.classList;
-    for (const className of columnDef._columnCssClassName) {
-      classList.add(className);
-    }
+    elementRef.nativeElement.classList.add(...columnDef._columnCssClassName);
   }
 }
 

src/material/table/_table-flex-styles.scss

@@ -26,15 +26,6 @@ $row-horizontal-padding: 24px;
     border-style: solid;
     align-items: center;
     box-sizing: border-box;
-
-    // Workaround for https://goo.gl/pFmjJD in IE 11. Adds a pseudo
-    // element that will stretch the row the correct height. See:
-    // https://connect.microsoft.com/IE/feedback/details/802625
-    &::after {
-      display: inline-block;
-      min-height: inherit;
-      content: '';
-    }
   }
 
   mat-cell, mat-header-cell, mat-footer-cell {

src/material/table/table.md

@@ -110,17 +110,17 @@ For most real-world applications, providing the table a `DataSource` instance wi
 manage data. The `DataSource` is meant to serve as a place to encapsulate any sorting, filtering,
 pagination, and data retrieval logic specific to the application.
 
-A `DataSource` is simply a class that has at a minimum the following methods: `connect` and 
-`disconnect`. The `connect` method will be called by the table to provide an `Observable` that emits 
+A `DataSource` is simply a class that has at a minimum the following methods: `connect` and
+`disconnect`. The `connect` method will be called by the table to provide an `Observable` that emits
 the data array that should be rendered. The table will call `disconnect` when the table is destroyed,
-which may be the right time to clean up any subscriptions that may have been registered in the 
-`connect` method. 
+which may be the right time to clean up any subscriptions that may have been registered in the
+`connect` method.
 
 Although Angular Material provides a ready-made table `DataSource` class, `MatTableDataSource`, you may
-want to create your own custom `DataSource` class for more complex use cases. This can be done by 
-extending the abstract `DataSource` class with a custom `DataSource` class that then implements the 
-`connect` and `disconnect` methods. For use cases where the custom `DataSource` must also inherit 
-functionality by extending a different base class, the `DataSource` base class can be 
+want to create your own custom `DataSource` class for more complex use cases. This can be done by
+extending the abstract `DataSource` class with a custom `DataSource` class that then implements the
+`connect` and `disconnect` methods. For use cases where the custom `DataSource` must also inherit
+functionality by extending a different base class, the `DataSource` base class can be
 implemented instead (`MyCustomDataSource extends SomeOtherBaseClass implements DataSource`) to
 respect Typescript's restriction to only implement one base class.
 
@@ -357,9 +357,6 @@ To do this, add the `sticky` or `stickyEnd` directive to the `ng-container` colu
 
 <!--- example(table-sticky-columns) -->
 
-This feature is supported by Chrome, Firefox, Safari, and Edge. It is not supported in IE, but
-it does fail gracefully so that the rows simply do not stick.
-
 Note that on Safari mobile when using the flex-based table, a cell stuck in more than one direction
 will struggle to stay in the correct position as you scroll. For example, if a header row is stuck
 to the top and the first column is stuck, then the top-left-most cell will appear jittery as you