Fix an issue where method prototypes have different signatures
Fix an issue where method prototypes have different signatures

Summary: PHP whines about this:

> [2013-09-23 08:09:22] ERROR 2048: Declaration of CSharpToolsTestEngine::loadEnvironment() should be compatible with XUnitTestEngine::loadEnvironment($config_item = 'unit.xunit...') at [/INSECURE/devtools/arcanist/src/unit/engine/CSharpToolsTestEngine.php:13]

Auditors: jamesr, btrahan

hach-que/arcanist,r4nt/arcanist,memsql/arcanist,calblueprint/arcanist,aik099/arcanist,folsom-labs/arcanist,wharris/arcanist,Khan/arcanist,coursera/arcanist,dguo-coursera/arcanist,aik099/arcanist,hach-que/arcanist,chundongwang/arcanist,r4nt/arcanist,r4nt/arcanist,kevinseelbach/arcanist,sneakpeeq/arcanist,alexmv/arcanist,memsql/arcanist,KieranHayes/arcanist,coursera/arcanist,wharris/arcanist,haskell-infra/arcanist,haskell-infra/arcanist,wharris/arcanist,zhihu/arcanist,Symplicity/arcanist,uber/arcanist,memsql/arcanist,codelabs-ch/arcanist,codelabs-ch/arcanist,wharris/arcanist,dguo-coursera/arcanist,Khan/arcanist,PageUpPeopleOrg/arcanist-patches,fivestars/arcanist,zhihu/arcanist,eSpark/arcanist,chundongwang/arcanist,codelabs-ch/arcanist,r4nt/arcanist,KieranHayes/arcanist,jra3/arcanist,phacility/arcanist,julkiewicz/arcanist,memsql/arcanist,calblueprint/arcanist,jra3/arcanist,eSpark/arcanist,chundongwang/arcanist,PageUpPeopleOrg/arcanist-patches,Symplicity/arcanist,phacility/arcanist,wxstars/arcanist,aik099/arcanist,dguo-coursera/arcanist,alexmv/arcanist,uber/arcanist,codelabs-ch/arcanist,kevinseelbach/arcanist,folsom-labs/arcanist,wikimedia/phabricator-arcanist,calblueprint/arcanist,haskell-infra/arcanist,aik099/arcanist,fivestars/arcanist,coursera/arcanist,jra3/arcanist,coursera/arcanist,dguo-coursera/arcanist,alexmv/arcanist,wikimedia/phabricator-arcanist,KieranHayes/arcanist,Khan/arcanist,PageUpPeopleOrg/arcanist-patches,julkiewicz/arcanist,sneakpeeq/arcanist,jra3/arcanist,haskell-infra/arcanist,wikimedia/phabricator-arcanist,Symplicity/arcanist,zhihu/arcanist,wxstars/arcanist,codelabs-ch/arcanist,hach-que/arcanist,phacility/arcanist,PageUpPeopleOrg/arcanist-patches,wikimedia/phabricator-arcanist,eSpark/arcanist,folsom-labs/arcanist,sneakpeeq/arcanist,wxstars/arcanist,phacility/arcanist,zhihu/arcanist,folsom-labs/arcanist,chundongwang/arcanist,eSpark/arcanist,sneakpeeq/arcanist,Khan/arcanist,phacility/arcanist,wxstars/arcanist,kevinseelbach/arcanist,KieranHayes/arcanist,hach-que/arcanist,fivestars/arcanist,julkiewicz/arcanist,julkiewicz/arcanist,Symplicity/arcanist,uber/arcanist,kevinseelbach/arcanist,calblueprint/arcanist,uber/arcanist,fivestars/arcanist,alexmv/arcanist