fix(scrolling): adds right to fix pushed content (#11192)

* fix(scrolling): adds right to fix pushed content

* chore: address feedback

* chore: address pr feedback

Author: amcdnl

src/cdk-experimental/scrolling/virtual-scroll-viewport.scss

@@ -14,6 +14,14 @@ cdk-virtual-scroll-viewport {
   will-change: contents, transform;
 }
 
+.virtual-scroll-orientation-horizontal {
+  bottom: 0;
+}
+
+.virtual-scroll-orientation-vertical {
+  right: 0;
+}
+
 // Spacer element that whose width or height will be adjusted to match the size of the entire data
 // set if it were rendered all at once. This ensures that the scrollable content region is the
 // correct size.

src/cdk-experimental/scrolling/virtual-scroll-viewport.ts

@@ -42,6 +42,8 @@ function rangesEqual(r1: ListRange, r2: ListRange): boolean {
   styleUrls: ['virtual-scroll-viewport.css'],
   host: {
     'class': 'cdk-virtual-scroll-viewport',
+    '[class.virtual-scroll-orientation-horizontal]': 'orientation === "horizontal"',
+    '[class.virtual-scroll-orientation-vertical]': 'orientation === "vertical"',
   },
   encapsulation: ViewEncapsulation.None,
   changeDetection: ChangeDetectionStrategy.OnPush,