Controlled numeric input gets cleared when unfocused

<!-- Note: if the issue is about documentation or the website, please file it at: https://github.com/reactjs/reactjs.org/issues/new --> **Do you want to request a *feature* or report a *bug*?** I would like to report a bug. **What is the current behavior?** A numeric input field gets cleared accidentally on several occasions. **If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem. Your bug will get fixed much faster if we can run your code and it doesn't have dependencies other than React. Paste the link to your JSFiddle (https://jsfiddle.net/Luktwrdm/) or CodeSandbox (https://codesandbox.io/s/new) example below:** 1. Open [this sandbox](https://codesandbox.io/embed/sad-rgb-mltuj) 2. Type “12.” into the field, with the trailing decimal separator 3. Unfocus the control 4. Append “.” to the field’s value to see “12..” 5. Unfocus the control once again and see that the number has completely disappeared **What is the expected behavior?** Similar to how uncontrolled inputs work (remove the `value` prop and then repeat the steps above), the input should not be cleared on blur. **Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?** I’m using React 16.12.0 and experienced the same behavior with the latest version of Chrome and iOS Safari. Regarding this bug, I have no experience with previous versions of React.