[ModuleInterface] Add printing for new attributes

Specially print @_hasMissingDesignatedInitializers and @_inheritsConvenienceInitializers in module interfaces

Fixes rdar://51249311

test/ModuleInterface/non-public-designated-inits.swift

@@ -0,0 +1,21 @@
+// Note: This test has a client: non-public-designated-inits-client.swift
+
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-frontend -typecheck %s -emit-module-interface-path %t/Module.swiftinterface -module-name Module -enable-library-evolution
+// RUN: %FileCheck %s < %t/Module.swiftinterface
+
+// CHECK: @_hasMissingDesignatedInitializers open class A {
+open class A {
+  // This is a non-public designated init, which means the convenience
+  // init should not be inheritable.
+  init() {}
+
+  // CHECK-NEXT: public init(_: Swift.Int)
+  public init(_: Int) {}
+
+  // CHECK-NEXT: convenience public init(hi: ())
+  public convenience init(hi: ()) { self.init() }
+
+// CHECK: }
+}