message: perf(devtools): faster bar chart formatting
  The array allocation in `addSpaces` was talking a lot of time. We were also recomputing same result very frequently.
diff: @@ -36,6 +36,7 @@ export class BarGraphFormatter extends RecordFormatter<BargraphNode> {
  addFrame(nodes: BargraphNode[], elements: ElementProfile[]): number {
  let timeSpent = 0;
  + const suffix = addSpaces(nodes.length);
  elements.forEach((element) => {
  // Possibly undefined because of
  // the insertion on the backend.
  @@ -50,7 +51,7 @@ export class BarGraphFormatter extends RecordFormatter<BargraphNode> {
  element.directives.forEach((dir) => {
  const innerNode: BargraphNode = {
  value: super.getDirectiveValue(dir),
  - name: dir.name + addSpaces(nodes.length),
  + name: dir.name + suffix,
  original: element,
  };
  nodes.push(innerNode);
  @@ -60,4 +61,4 @@ export class BarGraphFormatter extends RecordFormatter<BargraphNode> {
  }
  }
  -const addSpaces = (length: number) => Array.from(Array(length).keys()).reduce((acc, _) => acc + ' ', '');
  +const addSpaces = (length: number) => ' '.repeat(length);
  