Repeated evaluation of a non-capturing class declaration returns the same class object #11759

A class declaration with no captures that is evaluated more than once yields the same class object each time. Node creates a fresh class on every evaluation.

function f() { class K {} return K; }
console.log(f() === f());            // node: false   perry: true
const a = f(), b = f();
(a.prototype as any).x = 1;
console.log((new b() as any).x);     // node: undefined   perry: 1

The same happens for a non-capturing class declared in a loop body at module top level. Classes that capture variables are already fresh per evaluation, which is why the fixture in #11758 uses capturing classes for these cases.

Fixing this changes how classes inside bundle wrapper functions are compiled: CJS and esbuild bundles declare classes in functions that usually run once. So before changing the default, it needs a real-code census (tsc, Zod, the corpus) of how many repeated class evaluations actually happen and what per-evaluation class creation costs.

Found while fixing #11758.