Editor token colors stylesheet is only attached to DOM after the first editor was attached

[mofux]

monaco-editor version: 0.20.0
Browser: Chrome
OS: MacOS
Playground code that reproduces the issue:

After upgrading to 0.20.0 I've noticed that running monaco.editor.colorize will not highlight the produced output anymore. The tokens are there, and the token classes are set correctly (mtk{n}), but the styles for these tokens are missing (the style element with the monaco-colors class is missing).

Once adding the first editor to the page, the stylesheet gets added to the DOM and everything works as expected.

It's possible to call standaloneThemeService.get()._registerRegularEditorContainer() manually, but that's obviously quite a hack.

I think this change has introduced the regression:
microsoft/vscode@c201d89