Alternate title: _Applying #6684-similar fix to stroke_
#6684 makes sure the "current" transformation, at the moment of filling radial gradients is the `baseTransform` (that of the rescource (page), as it says in the specs). However, this should also be fixed in [`CanvasGraphics_stroke`](https://github.com/dsprenkels/pdf.js/blob/a9081653fc565eb72c3eb5142c17088cb162e7ce/src/display/canvas.js#L1052).

const groupCtx = this.ctx;
      this.groupLevel--;
      this.ctx = this.groupStack.pop();
      composeSMask(this.ctx, this.current.activeSMask, groupCtx);
      this.ctx.restore();
      copyCtxState(groupCtx, this.ctx);
      
      
      const deltaTransform = Util.transform(
        this.current.activeSMask.startTransformInverse,
        groupCtx.mozCurrentTransform
      );
      this.ctx.transform.apply(this.ctx, deltaTransform);
    }
    save() {
      this.ctx.save();
      const old = this.current;
      this.stateStack.push(old);
      this.current = old.clone();
      this.current.resumeSMaskCtx = null;
    }
    restore() {