[Security] Disabled the BCryptPasswordEncoder tests for PHP versions lower than 5.3.7.

See https://github.com/ircmaxell/password_compat/issues/10#issuecomment-11203833.
merged branch jakzal/testfix/bcrypt-before-5-3-7 (PR #8009)

This PR was merged into the master branch.

Discussion
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[Security] Disabled the BCryptPasswordEncoder tests for PHP < 5.3.7

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | no (segfault)
| Fixed tickets | #7994
| License       | MIT
| Doc PR        | -

See https://github.com/ircmaxell/password_compat/issues/10#issuecomment-11203833.

Commits
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3beaf52 [Security] Disabled the BCryptPasswordEncoder tests for PHP versions lower than 5.3.7.
Switched to phpunit installed with composer.
Fixed the autoloader.
Displayed phpunit versions.