fix(progress-spinner): rotating circle changing surrounding layout

When the progress spinner is rotating its layout can outside that of the parent which can have an effect on scroll bars. These changes put the rotating animation on the `svg` node and make the component host `overflow: hidden`.

Fixes #16894.

Author: crisbeto

src/material/progress-spinner/progress-spinner.scss

@@ -13,6 +13,10 @@ $_mat-progress-spinner-default-circumference: $pi * $_mat-progress-spinner-defau
   display: block;
   position: relative;
 
+  // Prevents the animating circle from going outside the bounds of the host
+  // and potentially changing the surrounding layout. See #16894.
+  overflow: hidden;
+
   svg {
     position: absolute;
     transform: rotate(-90deg);
@@ -30,9 +34,11 @@ $_mat-progress-spinner-default-circumference: $pi * $_mat-progress-spinner-defau
   }
 
   &.mat-progress-spinner-indeterminate-animation[mode='indeterminate'] {
-    @include _noop-animation();
-    animation: mat-progress-spinner-linear-rotate $swift-ease-in-out-duration * 4
-        linear infinite;
+    svg {
+      @include _noop-animation();
+      animation: mat-progress-spinner-linear-rotate $swift-ease-in-out-duration * 4
+          linear infinite;
+    }
 
     circle {
       @include _noop-animation();
@@ -45,11 +51,13 @@ $_mat-progress-spinner-default-circumference: $pi * $_mat-progress-spinner-defau
   }
 
   &.mat-progress-spinner-indeterminate-fallback-animation[mode='indeterminate'] {
-    @include _noop-animation();
-    animation: mat-progress-spinner-stroke-rotate-fallback
-               $mat-progress-spinner-stroke-rotate-fallback-duration
-               $mat-progress-spinner-stroke-rotate-fallback-ease
-               infinite;
+    svg {
+      @include _noop-animation();
+      animation: mat-progress-spinner-stroke-rotate-fallback
+                 $mat-progress-spinner-stroke-rotate-fallback-duration
+                 $mat-progress-spinner-stroke-rotate-fallback-ease
+                 infinite;
+    }
 
     circle {
       @include _noop-animation();