Fix objc_implementation_objc_client test

Because this test is disabled, a previous commit failed to add an experimental feature flag that’s required to run it.

Author: beccadax

test/Interpreter/objc_implementation_objc_client.m

@@ -8,7 +8,7 @@
 // RUN: %empty-directory(%t-frameworks/objc_implementation.framework/Headers)
 // RUN: cp %S/Inputs/objc_implementation.modulemap %t-frameworks/objc_implementation.framework/Modules/module.modulemap
 // RUN: cp %S/Inputs/objc_implementation.h %t-frameworks/objc_implementation.framework/Headers
-// RUN: %target-build-swift-dylib(%t-frameworks/objc_implementation.framework/objc_implementation) -emit-module-path %t-frameworks/objc_implementation.framework/Modules/objc_implementation.swiftmodule/%module-target-triple.swiftmodule -module-name objc_implementation -F %t-frameworks -import-underlying-module -Xlinker -install_name -Xlinker %t-frameworks/objc_implementation.framework/objc_implementation %S/objc_implementation.swift
+// RUN: %target-build-swift-dylib(%t-frameworks/objc_implementation.framework/objc_implementation) -emit-module-path %t-frameworks/objc_implementation.framework/Modules/objc_implementation.swiftmodule/%module-target-triple.swiftmodule -module-name objc_implementation -F %t-frameworks -import-underlying-module -Xlinker -install_name -Xlinker %t-frameworks/objc_implementation.framework/objc_implementation %S/objc_implementation.swift -enable-experimental-feature CImplementation
 
 //
 // Execute this file