Update Acornima to 1.3.0 and enable RegExp modifiers

[Copilot]

This updates Jint to Acornima 1.3.0 and turns on Acornima's new experimental RegExp modifiers support. It also removes the broad Test262 exclusion for regexp-modifiers and keeps only the remaining file-level skips that still reflect .NET regex semantic differences.

• Dependency update

  • Bump Acornima and Acornima.Extras to 1.3.0.

• Parser feature enablement

  • Add ExperimentalESFeatures.RegExpModifiers to Jint's base Acornima parser options so the new syntax is accepted consistently across script/module parsing and runtime regexp adaptation.

• Test262 coverage expansion

  • Remove the suite-level regexp-modifiers exclusion.
  • Replace it with a small set of targeted file exclusions for the cases that still diverge because of underlying .NET regex behavior:
    • scoped \b / \B
    • scoped \w / \W
    • scoped multiline anchor semantics

• Regression coverage

  • Add focused runtime coverage for RegExp modifiers in both regexp literals and new RegExp(...).

Example of the newly enabled syntax:

const literal = /(?m-i:^a$)/i;
const ctor = new RegExp("(?m-i:^a$)", "i");

literal.test("A\n"); // false
literal.test("a\n"); // true
ctor.test("A\n");    // false
ctor.test("a\n");    // true

Original prompt

see new acornima release https://github.com/adams85/acornima/releases/tag/v1.3.0 . create a pr to update it. make sure you enable the new experimental feature and remove as many test262 settings json excludes as you can for regexp - test262 settings need to still pass of course

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[lahma]

@copilot how many more tests are now passing, four excluded now, how many unexcluded

[Copilot]

@copilot how many more tests are now passing, four excluded now, how many unexcluded

It’s 128 more passing tests. The blanket feature exclusion is gone, and there are 6 file-level exclusions left, which show up as 12 skipped cases because Test262 runs them in both strict and non-strict modes. So for regexp-modifiers the current split is: 128 passing, 12 skipped, 140 total. Commit: 662433b