Fix the case for eval["']expr["'] and add regression tests.

eval EXPR could be no spaces between eval and EXPR for the case of eval'string'. However, the following regexp is used:

    s/eval\s+(['"])(.*?)\1/$2;/

It should be

    s/eval\s*(['"])(.*?)\1/$2;/

Corresponding tests are added.

NOTE: I am working on another pull request. If this pull request is accepted, I will make another one soon.