fix: memory leak call stack widget

[SimonSiefke]

Fixes a memory leak in call stack widget.

Details

In setFrames, a new disposable seems to be registered each time using this._register:

/** Replaces the call frames display in the view. */
public setFrames(frames: AnyStackFrame[]): void {
	// cancel any existing load
	this.currentFramesDs.clear();
	this.cts = new CancellationTokenSource();
	this._register(toDisposable(() => this.cts!.dispose(true)));

	this.list.splice(0, this.list.length, this.mapFrames(frames));
}

E.g. when setFrames is called 10 times, 10 disposables would be registered to the class.

Fix

By registering the disposable to currentFramesDs instead of using this._register, there will be at most one of this disposable registered. Similar to how mapFrames also uses currentFramesDs instead of this._register.

/** Replaces the call frames display in the view. */
public setFrames(frames: AnyStackFrame[]): void {
	// cancel any existing load
	this.currentFramesDs.clear();
	const cts = new CancellationTokenSource();
	this.currentFramesDs.add(toDisposable(() => cts.dispose(true)));
	this.cts = cts;

	this.list.splice(0, this.list.length, this.mapFrames(frames));


}

Before

When opening the test view using the test-provider extension sample and running tests 97 times, the number of functions in CallStackWidget.setFrames seems to grow by 1 each time:

After

When opening the test view using the test-provider extension sample and running tests 97 times, while the number of some functions still grows, the number of functions in CallStackWidget.setFrames stays constant:

[connor4312]

thanks!