MatPaginatedTabHeader doesn't scroll last tab fully into view

#### Reproduction

Use StackBlitz to reproduce your issue: https://stackblitz.com/edit/components-issue-wsbxpk

Steps to reproduce:
1. Set selectedIndex to last tab
2. Render

#### Expected Behavior

Selected tab is scrolled fully into view and righthand pagination button disabled just as if the user manually clicked on the last tab

#### Actual Behavior

Tab is only partially visible and pagination button remains enabled. When tab titles vary in size only a few pixels of the last tab are visible. Clicking on the last tab manually scrolls it fully into view.

#### Environment

- Angular: 8.2.14
- CDK/Material: 8.2.3
- Browser(s): Chrome, Firefox, Internet Explorer 11, Safari
- Operating System (e.g. Windows, macOS, Ubuntu): All

从链接的 StackBlitz 复现和 MatPaginatedTabHeader 实现开始，将 selectedIndex 设置为最后一个选项卡。比较初始渲染与手动选择最后一个选项卡时的情况，然后验证所选选项卡是否完全可见，以及右侧分页按钮是否已禁用。

由索引模型根据 Issue 内容生成。