[test-suite] Fix custom section test on MachO Platforms

Fix the tests added in https://reviews.llvm.org/D154673 to work on apple
platforms.

Reviewed By: daltenty

Differential Revision: https://reviews.llvm.org/D156462

Author: cachemeifyoucan

SingleSource/Regression/C++/custom_section_members.cpp

@@ -1,8 +1,13 @@
 // Test that we can compile a simple class with members in a custom section.
+#if defined(__APPLE__)
+#define SECTNAME "__TEXT,__section"
+#else
+#define SECTNAME "section"
+#endif
 
 struct A {
-  static int foo() __attribute__((section("section")));
-  static void bar() __attribute__((section("section")));
+  static int foo() __attribute__((section(SECTNAME)));
+  static void bar() __attribute__((section(SECTNAME)));
 };
 
 int A::foo() { return 0; }