Fix protoInit call injection timing

[JLHwung]

Q	A
Fixed Issues?	Babel runs method initializers added by context.addInitializers after undecorated field initializer (REPL), fixes #16188
Patch: Bug Fix?	Yes
Major: Breaking Change?
Minor: New Feature?
Tests Added + Pass?	Yes
Documentation PR Link
Any Dependency Changes?
License	MIT

This PR includes commits from #16234, I will rebase once that PR gets merged.

Per spec: InitializeInstanceElements

The method initializers should run before any fields are defined.

In the REPL example,

let initCalled;

function dec(value, context) {
  context.addInitializer(() => initCalled = true);
}

class C {
  @dec m() {}
  p = initCalled;
}

console.log((new C).p)

When the property p is defined, the initCalled should be true. Previously we inject the protoInit calls in the first decorated field, in this PR we move the field initializer injection out of the hasDecorators branch.

[babel-bot]

Build successful! You can test your changes in the REPL here: https://babeljs.io/repl/build/56192/

[JLHwung]

In the current main branch, f is printed before m3,m4,m5,m6,g3,g4,g5,g6,s3,s4,s5,s6.