test cxx mode in clang-includes tests

Author: hnrklssn

test/Interop/C/swiftify-import/clang-includes-explicit.swift

@@ -4,6 +4,7 @@
 // RUN: split-file %s %t
 
 // RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/ClangIncludesExplicit.swiftmodule -I %t/Inputs -enable-experimental-feature SafeInteropWrappers %t/test.swift
+// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/ClangIncludesExplicit.swiftmodule -I %t/Inputs -enable-experimental-feature SafeInteropWrappers %t/test.swift -cxx-interoperability-mode=default
 
 //--- test.swift
 import A1.B1.C1.D1

test/Interop/C/swiftify-import/clang-includes-noexport.swift

@@ -4,6 +4,7 @@
 
 // swift-ide-test doesn't currently typecheck the macro expansions, so run the compiler as well
 // RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/ClangIncludesNoExport.swiftmodule -I %S/Inputs -enable-experimental-feature SafeInteropWrappers %s
+// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/ClangIncludesNoExport.swiftmodule -I %S/Inputs -enable-experimental-feature SafeInteropWrappers %s -cxx-interoperability-mode=default
 
 import ClangIncludesNoExportModule
 

test/Interop/C/swiftify-import/clang-includes.swift

@@ -4,6 +4,7 @@
 
 // swift-ide-test doesn't currently typecheck the macro expansions, so run the compiler as well
 // RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/ClangIncludes.swiftmodule -I %S/Inputs -enable-experimental-feature SafeInteropWrappers %s
+// RUN: %target-swift-frontend -emit-module -plugin-path %swift-plugin-dir -o %t/ClangIncludes.swiftmodule -I %S/Inputs -enable-experimental-feature SafeInteropWrappers %s -cxx-interoperability-mode=default
 
 import ClangIncludesModule