Investigate decorator initialization order re: renames of classes

> @copilot address the next CR comment and think hard about other edge cases

Investigated the CR comment on computed class-element names (`@dec class C { [C]() {} }`) and verified against real `tsc` (7.0.2, legacy decorators, ES2020/ES2022) using several variants: getter/setter computed names, a computed name with its own member decorator, a static property computed name, and a computed name inside a nested class within a method body. In every case, real `tsc` *does* substitute the class alias in computed class-member names (e.g. emits `[C_1.name]() {}`, not `[C.name]() {}`), including before the alias is actually assigned (this is a real, pre-existing bug/quirk in Strada's own emit, not something this PR should "fix"). I built `tsgo` and confirmed its output already matches `tsc`'s byte-for-byte for all these cases at the current `afb6df68` state.

So the CR suggestion to exclude computed class-element names from alias detection/substitution is incorrect — implementing it would make `tsgo` diverge from `tsc`. I made no code changes for this comment; current behavior is already correct.

_Originally posted by @Copilot in https://github.com/microsoft/typescript-go/issues/4650#issuecomment-5321088559_