Perform case-insensitive check for PHPUnit test finder to not return original file

Summary: PhpunitTestEngine incorrectly included some source files as tests when run on a case-insensive fiesystem. This fixes that behavior. It could introduce problems for case-sensive users, but it's extremely unlikely to be an issue in practice (who would put a file in both Tests/ and tests/ and expect different results for the two?)

Test Plan: arc unit before and after change on OS X. Stubs and autoloaders in .../tests/... directories are no longer picked up.

Reviewers: epriestley

Reviewed By: epriestley

CC: aurelijus, Korvin, aran

Differential Revision: https://secure.phabricator.com/D7048

src/unit/engine/PhpunitTestEngine.php

@@ -148,7 +148,7 @@ final class PhpunitTestEngine extends ArcanistBaseUnitTestEngine {
           // Don't look above the project root.
           continue;
         }
-        if (Filesystem::resolvePath($full_path) == $path) {
+        if (0 == strcasecmp(Filesystem::resolvePath($full_path), $path)) {
           // Don't return the original file.
           continue;
         }