Text is abnormally thin when setting allowTransparency=true with webgl renderer (even when color is opaque)

Text rendering is abnormally thin when allowTransparency=true with the webgl renderer even when the background color is completely opaque.

allowTransparency=false:

allowTransparency=true:

I think this is also mentioned in this comment in another bug.

Details

• Browser and browser version: Chrome 106.0.5249.119
• OS version: Linux (Debian)
• xterm.js version: ToT @ 376f0d99721b6ec056b15551f46237b80e24b55b

Steps to reproduce

1. Run the demo page
2. Set theme to light and font family to "Noto Sans Mono"
3. Execute echo -e '\033[33mhello world\033[m'
4. Observe that the rendering is OK
5. Check the "allowTransparency" toggle
6. Reload the webgl addon because the rendering is messed up: Uncheck and then check the webgl checkbox under "Addon". (I believe reloading the addon is NOT what is causing problem here)
7. Observe that the "hello world" text is abnormally thin

Note that the light theme have a completely opaque background, so the rendering theoretically should just be the same.