matTabLink `disabled` input should be `matTabLinkDisabled`

#### Reproduction

Use StackBlitz to reproduce your issue: https://stackblitz.com/edit/angular-zju32k

Steps to reproduce:
1. Put a tooltip on a `matTabLink`
2. Disabled the `matTabLink`

#### Expected Behavior

Tab should be disabled, and tooltip should show.

#### Actual Behavior

Tooltip did not show.

#### Notes/Thoughts

If the input is changed to `matTabLinkDisabled`, then `disabled` and `[disabled]="true"` should still be able to work. However, it would also be possible to use `matTabLinkDisabled`, which would make it possible to disable the `MatTabLink` specifically, without disabling any other directive on the element.

I *believe* this would be a non breaking change, as the input is declared in the `inputs` field on component:

```typescript
@Directive({
selector: '[mat-tab-link], [matTabLink]',
exportAs: 'matTabLink',
inputs: ['disabled', 'disableRipple', 'tabIndex'], // <== HERE
host: {
'class': 'mat-tab-link',
'[attr.aria-current]': 'active ? "page" : null',
'[attr.aria-disabled]': 'disabled',
'[attr.tabIndex]': 'tabIndex',
'[class.mat-tab-disabled]': 'disabled',
'[class.mat-tab-label-active]': 'active',
}
})
export class MatTabLink
```
So *my understanding* is right now, you can’t read the disabled field by name anyways.

#### Environment

- Angular: 8.2.11
- CDK/Material: 8.2.1
- Browser(s): Version 77.0.3865.120 (Official Build) (64-bit)
- Operating System (e.g. Windows, macOS, Ubuntu): Debian Rodette

Start with the StackBlitz reproduction and the MatTabLink directive declaration shown in the issue, focusing on its disabled input and tooltip interaction. Done means a disabled tab link still displays its tooltip, while both disabled and matTabLinkDisabled remain usable as described.

Written by the indexing model from the issue text.