Reproduction

With Stackblitz I can't reproduce it as dev tools is not working there.

https://ibb.co/XXjZw1r

Steps to reproduce:

1. Go to official Material page (https://material.angular.io/components/table/overview#sorting)
2. Press F12
3. Enable Paint flashing tool
4. See that if you hover mat-sort-header (not clicking it, just hover), the whole table will be rendered again and again for nothing (even if you leave the sort header).

Expected Behavior

If I have a complex page with Material table, I would not expect performance issues because of re-rendering the whole table on hovering mat-sort-header. Table's data definetely should not connect to mat-sort-header on hover event by default.

Actual Behavior

Causes performance issues.
https://ibb.co/XXjZw1r

Environment

• Angular: 9 latest
• CDK/Material: 9 latest
• Browser(s): Chrome
• Operating System (e.g. Windows, macOS, Ubuntu): Windows