summary
As discovered by @jridgewell and esbuild, our tests are all using import/export and yet some of them still do things that are technically illegal. They modify the namespaced import. For the full list see #33443 (comment).

Once all incorrect usages of esm are fixed, we can turn off module transpilation from our pre-esbuild babel transformation for out tests.

cc @jridgewell / @rsimha.

PS: @jridgewell: can you share the rule that let you discover the list of breakages?