Port ES2016 transform

[weswigham]

Which is just the exponentiation operators - ** and **=

[Copilot]

Pull Request Overview

This PR adds support for compiling ES2016 exponentiation operators (** and **=) by transforming them into Math.pow calls in down-level code and updates the corresponding test baselines.

• Introduced new transform for private static and instance field exponentiation assignments.
• Converted all exponentiation operator usages in conformance tests to Math.pow equivalents.
• Adjusted template-string, new-operator, and various syntax/error test cases to reflect the transformation.

Reviewed Changes

Copilot reviewed 107 out of 107 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
testdata/baselines/reference/submodule/conformance/privateNameStaticFieldAssignment.js.diff	Fixes for transforming A.#field **= n to Math.pow-based setter
testdata/baselines/reference/submodule/conformance/privateNameStaticFieldAssignment.js	Updated baseline for private static field exponentiation
testdata/baselines/reference/submodule/conformance/privateNameFieldAssignment.js.diff	Fixes for transforming this.#field **= n to Math.pow-based setter
testdata/baselines/reference/submodule/conformance/privateNameFieldAssignment.js	Updated baseline for private instance field exponentiation
testdata/baselines/reference/submodule/conformance/parseRegularExpressionMixedWithComments.js.diff	Revised regex/comment parsing tests alongside exponentiation changes
testdata/baselines/reference/submodule/conformance/parseRegularExpressionMixedWithComments.js	Updated baseline for mixed regex/comment tests
testdata/baselines/reference/submodule/conformance/jsDeclarationsFunctionLikeClasses2.js.diff	Reverted ** 2 back to Math.pow(...,2) in vector magnitude
testdata/baselines/reference/submodule/conformance/jsDeclarationsFunctionLikeClasses2.js	Baseline update for ES6 class declaration transform
testdata/baselines/reference/submodule/conformance/jsDeclarationsFunctionLikeClasses.js.diff	Converted inline ** usage in function declarations to Math.pow
testdata/baselines/reference/submodule/conformance/jsDeclarationsFunctionLikeClasses.js	Updated baseline for function-like class declarations
testdata/baselines/reference/submodule/conformance/*	Bulk update of exponentiation operator to Math.pow across template-strings, compound assignments, syntax-error tests, and other conformance cases

Comments suppressed due to low confidence (2)

testdata/baselines/reference/submodule/conformance/privateNameStaticFieldAssignment.js.diff:54

• The diff prefix -+ is invalid. It should be just - to remove the A.#field **= 6; line.

+        A.#field *= 5;

testdata/baselines/reference/submodule/conformance/privateNameFieldAssignment.js.diff:55

• The diff prefix -+ is invalid. It should be just - to remove the this.#field **= 6; line.

+        this.#field *= 5;

[jakebailey]

I didn't even know JS had this operator

[weswigham]

I didn't even know JS had this operator

It has funky rules because coming to consensus is hard. Most things need parens on the LHS to work, by choice, even though it's not required to parse it. Most notably, -2 ** 2 is just invalid code, because nobody wanted to dictate if it was equivalent to (-2) ** 2 or -(2 ** 2).