regex /iv character class fails to match a case equivalent #1752

Build environment: macOS 27.0 (build 26A428), arm64
Moddable SDK version: 10.0.0 (commit 5f215f7)
Target device: macOS desktop XS test shell (xst)

Description
A character class containing S fails to match lowercase s with the i and v flags.

Steps to Reproduce

print(/^[S\u{1F600}]$/iv.test("s")); // prints false

run xst -s repro.js

Expected behavior
prints true