[Tabs] Dynamic height does not work when content has changed

#### Bug, feature request, or proposal:
Bug

#### What is the expected behavior?
Tabs should transition height properly when content is added dynamically.

#### What is the current behavior?
Adding content to a tab does not modify the 'base animation height' resulting in weird animations.

#### What are the steps to reproduce?
~~http://plnkr.co/edit/Sccmy7os1nuaELrradRv?p=preview~~
~~http://plnkr.co/edit/ZSBCT8P9xCi04rrKSCu3?p=preview~~
https://stackblitz.com/edit/angular-humdjf?file=src%2Fapp%2Fapp.component.html
Add content dynamically and change tab.

#### Is there anything else we should know?
~~Documentation is missing for dynamicHeight on material.angular.io~~

从链接的 StackBlitz 复现开始，尤其检查 src/app/app.component.html，并检查 Angular Material 针对 dynamicHeight 的选项卡实现。通过动态添加内容并切换选项卡来复现该问题；当选项卡高度过渡使用更新后的内容尺寸时，即表示完成。

由索引模型根据 Issue 内容生成。