[ParseableInterface] Don't require Foundation to use @objc

Deinitializers are always @objc. (Arguably, this makes it unnecessary
to print, but we don't want to do any @objc inference at all in a
swiftinterface.)

Author: jrose-apple

lib/Frontend/ParseableInterfaceSupport.cpp

@@ -157,6 +157,10 @@ ParseableInterfaceModuleLoader::configureSubInvocationAndOutputPaths(
   // by making them non-fatal).
   SubInvocation.getLangOptions().DebuggerSupport = LangOpts.DebuggerSupport;
 
+  // Disable this; deinitializers always get printed with `@objc` even in
+  // modules that don't import Foundation.
+  SubInvocation.getLangOptions().EnableObjCAttrRequiresFoundation = false;
+
   // Calculate an output filename that includes a hash of relevant key data, and
   // wire up the SubInvocation's InputsAndOutputs to contain both input and
   // output filenames.

test/ParseableInterface/ModuleCache/ObjCAttrWithoutFoundation.swiftinterface

@@ -0,0 +1,10 @@
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name ObjCAttrWithoutFoundation -enable-resilience -enable-objc-interop
+
+// RUN: %empty-directory(%t)
+// RUN: echo 'import ObjCAttrWithoutFoundation' | %target-swift-frontend -typecheck -enable-parseable-module-interface -module-cache-path %t -I %S -
+
+public class MyClass {
+  public init()
+  @objc deinit
+}