Fix tdz checks in transform-block-scoping plugin (#9498)

* Better tdz tests

- Use jest's expect.toThrow/expect.not.toThrow
- Add input/output tests

* Fix basic tdz (a = 2; let a)

Fixes #6848

* Make _guessExecutionStatusRelativeTo more robust

* Add tests

* Return less "unkown" execution status

* "function" execution status does not exist

* Fix recursive functions

* Update helper version

* "finally" blocks are always executed

* Typo

packages/babel-plugin-transform-block-scoping/test/fixtures/tdz/function-call-nested-function/exec.js

@@ -0,0 +1,17 @@
+expect(() => {
+  function f() {
+    return function() { x };
+  }
+  let g = f();
+  let x;
+  g();
+}).not.toThrow();
+
+expect(() => {
+  function f() {
+    return function() { x };
+  }
+  let g = f();
+  g();
+  let x;
+}).toThrow(ReferenceError);

packages/babel-plugin-transform-block-scoping/test/fixtures/tdz/function-call-nested-function/input.js

@@ -0,0 +1,5 @@
+function f() {
+  return function() { x };
+}
+f();
+let x;

packages/babel-plugin-transform-block-scoping/test/fixtures/tdz/function-call-nested-function/output.js

@@ -0,0 +1,11 @@
+var x = babelHelpers.temporalUndefined;
+
+function f() {
+  return function () {
+    babelHelpers.temporalRef(x, "x");
+  };
+}
+
+f();
+x = void 0;
+void 0;