message: Fix TextureMetrics wrong cache
diff: @@ -206,7 +206,7 @@ export class TextMetrics
  let line = '';
  let lines = '';
  - const cache: CharacterWidthCache = {};
  + const cache: CharacterWidthCache = Object.create(null);
  const { letterSpacing, whiteSpace } = style;
  // How to handle whitespaces
  @@ -418,7 +418,7 @@ export class TextMetrics
  {
  let width = cache[key];
  - if (width === undefined)
  + if (typeof width !== 'number')
  {
  const spacing = ((key.length) * letterSpacing);
  