Allow passing AST Tree directly.

[aliceofhartley]

Related PR

This PR is part of a set to allow for restringer to avoid recomputing the same flast to improve performance when working on large js files.

❯ npm run test

> obfuscation-detector@2.0.7 test
> node --test

▶ Detectors tests
  ✔ array_function_replacements_local_proxies (54.571507ms)
  ✔ array_replacements (10.816383ms)
  ✔ array_replacements_prototype_calls (8.661569ms)
  ✔ augmented_array_function_replacements (44.645347ms)
  ✔ augmented_proxied_array_function_replacements (166.253226ms)
  ✔ caesar_plus (5.681033ms)
  ✔ obfuscator.io-NotBooleanTilde (7.973299ms)
  ✔ obfuscator.io-setCookie (6.55019ms)
✔ Detectors tests (306.126756ms)
▶ Functionality
  ✔ Invalid input should not throw an error (4.421038ms)
  ✔ Invalid input should return an empty array (0.825095ms)
✔ Functionality (5.92106ms)
ℹ tests 10
ℹ suites 2
ℹ pass 10
ℹ fail 0
ℹ cancelled 0
ℹ skipped 0
ℹ todo 0
ℹ duration_ms 405.648285