Fix emit for object rest on a module export

[rbuckton]

Fixes the emit for object rest binding patterns on exported variables.

Also fixes a few other small tooling bugs:

• Fixes a bug in vary-by test configurations to allow running conformance/compiler tests against multiple module/target configurations.
• gulp diff and gulp diff-rwc no longer block until your diff tool is closed.
• You can add // @noTypesAndSymbols: true to the top of a test to skip .types and .symbols baselines if they're not relevant to the test.

Fixes #32656

[weswigham]

Do we have a test for the empty binding pattern - export const {} = {};? The emit for that seems strange in the playground.

[rbuckton]

Hmm. You are correct, those seem a bit odd.

[rbuckton]

We do this intentionally, even if its a bit strange and could be cleaned up. The idea is that we need to preserve any possible side effects of the initializer, and we're transforming a variable declaration to a variable declaration, so we need to emit something. Arguably, this could be cleaned up, but I don't believe that's related to the issue this intends to resolve.

[rbuckton]

I will add the tests, so that we can refer to them later and can validate regressions, but I don't intend to address the current emit for those in this PR.