Ensure the [[@@toPrimitive]] call of a decorated class member key is invoked once

[JLHwung]

Q	A
Fixed Issues?	The [[@@toPrimitive]] call is invoked more than once for the decorated accessor keys REPL
Patch: Bug Fix?	Yes
Major: Breaking Change?
Minor: New Feature?
Tests Added + Pass?	Yes
Documentation PR Link
Any Dependency Changes?
License	MIT

In the following example,

const logs = [];
const dec = (value, context) => {};
const f = () => { return { [Symbol.toPrimitive]: () => (logs.push("calling toPrimitive"), "f()") }; };
class Foo {
  @dec static accessor [f()];
}

console.log(logs);

The [[@@toPrimitive]] should be invoked only once during the ClassElementNameEvaluation, however, the transpiled code shows that it is run for 4 times (REPL).

In this PR we first unify the criteria of memoising computed keys, aligning it with the class properties transform here.

babel/packages/babel-helper-create-class-features-plugin/src/misc.ts

Lines 142 to 160 in 380d186

	// Make sure computed property names are only evaluated once (upon class definition)
	// and in the right order in combination with static properties
	if (!computedKey.isConstantExpression()) {
	const ident = path.scope.generateUidIdentifierBasedOnNode(
	computedNode.key,
	);
	// Declaring in the same block scope
	// Ref: https://github.com/babel/babel/pull/10029/files#diff-fbbdd83e7a9c998721c1484529c2ce92
	path.scope.push({
	id: ident,
	kind: "let",
	});
	declarations.push(
	t.expressionStatement(
	t.assignmentExpression("=", t.cloneNode(ident), computedNode.key),
	),
	);
	computedNode.key = t.cloneNode(ident);
	}

In the second commit we emit the toPropertyKey call when the caching the computed key and hardened out test suites.

[babel-bot]

Build successful! You can test your changes in the REPL here: https://babeljs.io/repl/build/55976/