Use "standalone" mode to launch logic tests

Summary: Always launch Logic tests in "standalone" mode, regardless of whether the the target sim is booted or not.

Reviewed By: Nekitosss

Differential Revision: D38456412

fbshipit-source-id: b64135b09eee3bc34b718d48af6fb3998d646c9d

XCTestBootstrap/Strategies/FBLogicTestRunStrategy.m

@@ -314,7 +314,7 @@ - (instancetype)initWithTarget:(id<FBiOSTarget, FBProcessSpawnCommands, FBXCTest
     [FBCollectionInformation oneLineDescriptionFromDictionary:environment]
   ];
   FBProcessIO *io = [[FBProcessIO alloc] initWithStdIn:nil stdOut:[FBProcessOutput outputForDataConsumer:outputs.stdOutConsumer] stdErr:[FBProcessOutput outputForDataConsumer:outputs.stdErrConsumer]];
-  FBProcessSpawnConfiguration *configuration = [[FBProcessSpawnConfiguration alloc] initWithLaunchPath:launchPath arguments:arguments environment:environment io:io mode:FBProcessSpawnModeDefault];
+  FBProcessSpawnConfiguration *configuration = [[FBProcessSpawnConfiguration alloc] initWithLaunchPath:launchPath arguments:arguments environment:environment io:io mode:FBProcessSpawnModePosixSpawn];
 
   return [[self.target
     launchProcess:configuration]