Enable statically analyzable TDZ checks by default

[nicolo-ribaudo]

Q	A
Fixed Issues?
Patch: Bug Fix?
Major: Breaking Change?
Minor: New Feature?
Tests Added + Pass?	Yes
Documentation PR Link
Any Dependency Changes?
License	MIT

Now that the TDZ transform is more stable, this PR enables TDZ checks for statically analyzable TDZ errors by default. In a future minor I would like to add a noDynamicTDZ assumption (that defaults to true) that, when not enabled, makes the block scoping plugin inject the dynamic TDZ checks.

The tdz option will then become unnecessary, and can be removed in Babel 8. It's currently one of the few options that require users to explicitly list the plugin in their config.

As a "spec compliancy" PR, I don't think that this one needs to wait for a minor.

This PR is blocked on fixing #15175, to avoid introducing a regression in the default behavior.

[babel-bot]

Build successful! You can test your changes in the REPL here: https://babeljs.io/repl/build/53671/

[liuxingbaoyu]

Hopefully this won't have a performance hit. I am worried that the default enablement may be too demanding for us, and any wrong scope information may cause problems, and it seems that there are not many users who enable the tdz option now.

FYI: https://bugs.webkit.org/show_bug.cgi?id=199866 TDZ validation has had serious performance issues even in browsers.

[nicolo-ribaudo]

I'll take some measurements.

[nicolo-ribaudo]

@liuxingbaoyu Wdyt about just having a noTDZ (defaults to true) assumption instead, without changing the default behavior? My end goal is to make it easier to enable tdz checks, and currently having it as a plugin option makes it hard.

[liuxingbaoyu]

This sounds good to me.
I'm not sure if @JLHwung would prefer TDZ + disabled by default.
babel/website#2701 (review)