Autocompletion overwrites following characters

Environment

• Operating System: Windows 10 Pro (64 bits)
• JDK version: JDK8_144, JDK8_151, , JDK8_152, OpenJdk8_144
• Visual Studio Code version: 1.17.2
• Java extension version: 0.12.0

Steps To Reproduce

1. [step 1] Type "<Integer>"
2. [step 2] Put cursor before "<Integer>", Type "Array", waiting for autocompletion to show "ArrayList". Select "ArrayList", several characters of the following "<Integer>" will be overwriten.

This bug can be easily reproduced on all java files.

Current Result

Sometimes "ArrayListInteger>", sometimes "ArrayListeger>", sometimes "ArrayList<Integer>"

Expected Result

"ArrayList<Integer>"