Investigate high CPU usage on Windows, due to parentProcessStillRunning()

[fbricon]

From https://gitter.im/Microsoft/vscode-java-debug?at=59d57a4101110b72317a3bca :

The issue is that the Redhat extension runs java.exe (eclipse_1624.dll), which continually 
runs cmd.exe, which runs  tasklist.exe and findstr.exe.  This causes high CPU usage.

As @andxu correctly points out, the jdt plugin:

will check task list periodically to find the process which starts it to keep the same
 life-cycle with it, the code is at 

https://github.com/eclipse/eclipse.jdt.ls/blob/98e1e50452d332ba2bbf9050ac1b23f6051ab5ea/org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/LanguageServer.java#L53-L57

and
https://github.com/eclipse/eclipse.jdt.ls/blob/98e1e50452d332ba2bbf9050ac1b23f6051ab5ea/org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/LanguageServer.java#L28

[gorkem]

We can easily avoid running findstr.

Is removing parentProcessStillRunning check completely an option?

[fbricon]

The parent process check is now only done after 30s of inactivity