Interop: restore -std=c++11 for a few tests

Restore the explicit C++ standard for these tests as the C++ compiler
invocation on Darwin uses the system compiler rather than the just built
clang, which may be sufficiently different to have different default
standards.

This will be cleaned up with the next change to introduce a new
`%target-clangxx` to control the C++ standard.

Author: compnerd

test/Interop/Cxx/operators/member-out-of-line.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-clang -c %S/Inputs/member-out-of-line.cpp -I %S/Inputs -o %t/member-out-of-line.o
+// RUN: %target-clang -std=c++11 -c %S/Inputs/member-out-of-line.cpp -I %S/Inputs -o %t/member-out-of-line.o
 // RUN: %target-build-swift %s -I %S/Inputs -o %t/member-out-of-line %t/member-out-of-line.o -Xfrontend -enable-cxx-interop
 // RUN: %target-codesign %t/member-out-of-line
 // RUN: %target-run %t/member-out-of-line

test/Interop/Cxx/operators/non-member-out-of-line.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-clang -c %S/Inputs/non-member-out-of-line.cpp -I %S/Inputs -o %t/non-member-out-of-line.o
+// RUN: %target-clang -std=c++11 -c %S/Inputs/non-member-out-of-line.cpp -I %S/Inputs -o %t/non-member-out-of-line.o
 // RUN: %target-build-swift %s -I %S/Inputs -o %t/non-member-out-of-line %t/non-member-out-of-line.o -Xfrontend -enable-cxx-interop
 // RUN: %target-codesign %t/non-member-out-of-line
 // RUN: %target-run %t/non-member-out-of-line

test/Interop/Cxx/reference/reference.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-clang -c %S/Inputs/reference.cpp -I %S/Inputs -o %t/reference.o
+// RUN: %target-clang -std=c++11 -c %S/Inputs/reference.cpp -I %S/Inputs -o %t/reference.o
 // RUN: %target-build-swift %s -I %S/Inputs -o %t/reference %t/reference.o -Xfrontend -enable-cxx-interop
 // RUN: %target-codesign %t/reference
 // RUN: %target-run %t/reference

test/Interop/Cxx/static/constexpr-static-member-var.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-clang -c %S/Inputs/static-member-var.cpp -I %S/Inputs -o %t/static-member-var.o
+// RUN: %target-clang -std=c++11 -c %S/Inputs/static-member-var.cpp -I %S/Inputs -o %t/static-member-var.o
 // NOTE: we must use `-O` here to ensure that the constexpr value is inlined and no undefined reference remains.
 // RUN: %target-build-swift -O %s -I %S/Inputs -o %t/statics %t/static-member-var.o -Xfrontend -enable-cxx-interop
 // RUN: %target-codesign %t/statics

test/Interop/Cxx/static/static-member-var.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-clang -c %S/Inputs/static-member-var.cpp -I %S/Inputs -o %t/static-member-var.o
+// RUN: %target-clang -std=c++11 -c %S/Inputs/static-member-var.cpp -I %S/Inputs -o %t/static-member-var.o
 // RUN: %target-build-swift %s -I %S/Inputs -o %t/statics %t/static-member-var.o -Xfrontend -enable-cxx-interop
 // RUN: %target-codesign %t/statics
 // RUN: %target-run %t/statics