SourceKit: add test for attributed imports in generated interfaces

Author: egorzhdan

test/IDE/print_attributed_imports.swift

@@ -0,0 +1,15 @@
+// RUN: %empty-directory(%t)
+
+// RUN: echo 'public func module1() {}' >> %t/module1.swift
+// RUN: echo 'public func module2() {}' >> %t/module2.swift
+// RUN: %target-swift-frontend -emit-module -module-name Module1 -o %t %t/module1.swift
+// RUN: %target-swift-frontend -emit-module -module-name Module2 -o %t %t/module2.swift
+
+// RUN: %target-swift-frontend -I %t -emit-module -o %t/AttrImports.swiftmodule %S/print_attributed_imports.swift
+// RUN: %target-swift-ide-test -I %t -print-module -source-filename %s -module-to-print=AttrImports | %FileCheck %s
+
+@_exported import Module1
+@_implementationOnly import Module2
+
+// CHECK: import Module1
+// CHECK-NOT: import Module2