Add button to double heap size on OOM

[datho7561]

Copied from vscode-java.

Closes #700

Signed-off-by: David Thompson davthomp@redhat.com

[datho7561]

I've tried testing the case where the user sets the vmargs to " ", so that no -Xmx is set within them. From what I can tell, this means that the Java VM takes 1/4 of the available physical memory as the Xmx. I am having trouble getting lemminx to crash under this circumstance, since most of my computers have decently large amounts of physical memory, and VS Code is not good at opening large files (It crashes and freezes before lemminx does). I'll try again in a memory constrained VM.

[datho7561]

Even on a memory constrained VM, I couldn't get the OOM message to appear when using empty jvm args.

[rgrunber]

Ok, so the subscription of the JDK Config changes happens before the LS starts interacting with the file.

Change looks good to me. Feel free to merge.