Editor GPU: Only write lines to the cell bind buffer when they change

[Tyriar]

vscode/src/vs/editor/browser/gpu/fullFileRenderStrategy.ts

Lines 239 to 245 in bd21f3c

	for (y = viewportData.startLineNumber; y <= viewportData.endLineNumber; y++) {
	// TODO: Update on dirty lines; is this known by line before rendering?
	// if (upToDateLines.has(y)) {
	// continue;
	// }
	dirtyLineStart = Math.min(dirtyLineStart, y);