Regressions in 6.0.0

[nicolo-ribaudo]

From Babel's test262:

not ok 11237 test/language/literals/regexp/u-astral-char-class-invert.js default # (expected success, got runtime error)
  ---
  name: Test262Error
  message: 'Expected SameValue(«�», «null») to be true'
  stack: >
    Test262Error: Expected SameValue(«�», «null») to be true

    /home/runner/work/babel/babel/babel-test262-runner/lib/run-tests/index.js:80:17

  ...
not ok 11239 test/language/literals/regexp/u-astral-char-class-invert.js strict mode # (expected success, got runtime error)
  ---
  name: Test262Error
  message: 'Expected SameValue(«�», «null») to be true'
  stack: >
    Test262Error: Expected SameValue(«�», «null») to be true

    /home/runner/work/babel/babel/babel-test262-runner/lib/run-tests/index.js:80:17

  ...
not ok 11262 test/language/literals/regexp/u-invalid-optional-lookahead.js default # (expected parser error, got runtime error)
  ---
  name: Test262
  message: This statement should not be evaluated.
  stack: >
    Test262: This statement should not be evaluated.

    /home/runner/work/babel/babel/babel-test262-runner/lib/run-tests/index.js:80:17

  ...
not ok 11263 test/language/literals/regexp/u-invalid-optional-lookahead.js strict mode # (expected parser error, got runtime error)
  ---
  name: Test262
  message: This statement should not be evaluated.
  stack: >
    Test262: This statement should not be evaluated.

    /home/runner/work/babel/babel/babel-test262-runner/lib/run-tests/index.js:80:17

  ...
not ok 11266 test/language/literals/regexp/u-invalid-optional-negative-lookahead.js strict mode # (expected parser error, got runtime error)
  ---
  name: Test262
  message: This statement should not be evaluated.
  stack: >
    Test262: This statement should not be evaluated.

    /home/runner/work/babel/babel/babel-test262-runner/lib/run-tests/index.js:80:17

  ...
not ok 11267 test/language/literals/regexp/u-invalid-optional-negative-lookahead.js default # (expected parser error, got runtime error)
  ---
  name: Test262
  message: This statement should not be evaluated.
  stack: >
    Test262: This statement should not be evaluated.

    /home/runner/work/babel/babel/babel-test262-runner/lib/run-tests/index.js:80:17

  ...
not ok 11270 test/language/literals/regexp/u-invalid-range-lookahead.js default # (expected parser error, got runtime error)
  ---
  name: Test262
  message: This statement should not be evaluated.
  stack: >
    Test262: This statement should not be evaluated.

    /home/runner/work/babel/babel/babel-test262-runner/lib/run-tests/index.js:80:17

  ...
not ok 11271 test/language/literals/regexp/u-invalid-range-lookahead.js strict mode # (expected parser error, got runtime error)
  ---
  name: Test262
  message: This statement should not be evaluated.
  stack: >
    Test262: This statement should not be evaluated.

    /home/runner/work/babel/babel/babel-test262-runner/lib/run-tests/index.js:80:17

  ...
not ok 11274 test/language/literals/regexp/u-invalid-range-negative-lookahead.js default # (expected parser error, got runtime error)
  ---
  name: Test262
  message: This statement should not be evaluated.
  stack: >
    Test262: This statement should not be evaluated.

    /home/runner/work/babel/babel/babel-test262-runner/lib/run-tests/index.js:80:17

  ...
not ok 11275 test/language/literals/regexp/u-invalid-range-negative-lookahead.js strict mode # (expected parser error, got runtime error)
  ---
  name: Test262
  message: This statement should not be evaluated.
  stack: >
    Test262: This statement should not be evaluated.

    /home/runner/work/babel/babel/babel-test262-runner/lib/run-tests/index.js:80:17

  ...
# 10 new failures, 0 new successes
1..10

@JLHwung Could you take a look? (I am downgrading to v5 for Babel 7.23.0, we can re-land the upgrade in a patch)