Polyfill Promise.withResolvers

[dbp]

Promise.withResolvers was introduced in 2023/2024 (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/withResolvers), and so anyone with current browsers will have it, but people who have older computers can't run current browsers -- e.g., had a student with macOS 13.2, and chrome seemed stuck at 116 (which is close! But need 119).

This may have been caused by image-file, since that was what caused it -- specifically, the program that triggered this is:

use context starter2024
include image
EAR = image-file("ear-1.png")
EAR

(If this type of issue should be reported at https://github.com/jpolitz/pyret-parley-vscode, sorry! I didn't actually look through the code for where exactly that call was being made)

[jpolitz]

Report it anywhere. Soon there will be a single repo to report everything.