Handle already hoisted bindings

[paddyobrien]

Motivation

Fixes https://github.com/callstack/linaria/issues/1047

Summary

This incorrectly failed with an "unsupported error" in cases where the identifier was already hoisted.

A couple of lines down from here we return early if the binding.scope.parent is falsey. So I think it's safe to let this through.

Test plan

I wasn't able to get the test suite (or bootstrap) to run with pnpm so I haven't included any tests.

It seems like it would be fairly easy to add a snapshot test along the lines of the following to the test file here:

  it('should work with already hoisted vars', async () => {
    const { code, metadata } = await transform(
      dedent`
        function color() {
          return 'red\
        }

        export const square = css\`
          color: ${'${color()}'}
      \`;
      `,
      [evaluator]
    );

    expect(code).toMatchSnapshot();
    expect(metadata).toMatchSnapshot();
  });