Don't have Xcode embed the Swift stdlib into SwiftXCTest.framework

This avoids issues arising from dyld trying to load both Xcode's
stdlib version and the just-built stdlib which may not be compatible.

Author: briancroom

XCTest.xcodeproj/project.pbxproj

@@ -449,7 +449,6 @@
 				DYLIB_COMPATIBILITY_VERSION = 1;
 				DYLIB_CURRENT_VERSION = 1;
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
-				EMBEDDED_CONTENT_CONTAINS_SWIFT = YES;
 				FRAMEWORK_VERSION = A;
 				INFOPLIST_FILE = Info.plist;
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
@@ -472,7 +471,6 @@
 				DYLIB_COMPATIBILITY_VERSION = 1;
 				DYLIB_CURRENT_VERSION = 1;
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
-				EMBEDDED_CONTENT_CONTAINS_SWIFT = YES;
 				FRAMEWORK_VERSION = A;
 				INFOPLIST_FILE = Info.plist;
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";