[clang] Remove unit test which uses reverse-iterate flag

[mgrang]

Summary

This patch is in response to https://reviews.llvm.org/D35043 which removed -reverse-iterate flag.

[mgrang]

This patch does 3 things:

1. Get rid of the unit test objc-modern-metadata-visibility2.mm because this test check uses flag -reverse-iterate. This flag will be removed in D35043.

2. D35043 gets rid of the empty base definition for PointerLikeTypeTraits. This results in a compiler warning because PointerLikeTypeTrait has been defined as struct here while in the header it is a class. So I have changed struct to class.

3. Since I changed struct PointerLikeTypeTrait to class PointerLikeTypeTrait here, the member functions are no longer public now. This results in a compiler error. So I explicitly marked them as public here.

[dblaikie]

sounds good - so long as other tests would fail if the fix this test was testing wasn't present (on a reverse iteration enabled build)

[mgrang]

In D36386#851853, @dblaikie wrote:

sounds good - so long as other tests would fail if the fix this test was testing wasn't present (on a reverse iteration enabled build)

Thanks! Yes, I verified that the test objc-modern-metadata-visibility.mm would fail in a reverse iteration build w/o the fix this was testing.

test/Rewriter/objc-modern-metadata-visibility2.mm

-// REQUIRES: abi-breaking-checks
-// NOTE: This test has been split from objc-modern-metadata-visibility.mm in
-// order to test with -reverse-iterate as this flag is only present with
-// ABI_BREAKING_CHECKS.
-
-// RUN: %clang_cc1 -E %s -o %t.mm -mllvm -reverse-iterate
-// RUN: %clang_cc1 -x objective-c++ -fblocks -fms-extensions -rewrite-objc %t.mm -mllvm -reverse-iterate -o - | FileCheck %s
-// rdar://11144048
-
-@class NSString;
-
-@interface NSObject {
-    Class isa;
-}
-@end
-
-@interface Sub : NSObject {
-    int subIvar;
-    NSString *nsstring;
-@private
-    id PrivateIvar;
-}
-@end
-
-@implementation Sub
-- (id) MyNSString { return subIvar ? PrivateIvar : nsstring; }
-@end
-
-@interface NSString @end
-@implementation NSString @end
-
-// CHECK: __declspec(allocate(".objc_ivar$B")) extern "C" __declspec(dllimport) unsigned long OBJC_IVAR_$_Sub$subIvar;
-// CHECK: __declspec(allocate(".objc_ivar$B")) extern "C" unsigned long OBJC_IVAR_$_Sub$PrivateIvar;
-// CHECK: __declspec(allocate(".objc_ivar$B")) extern "C" __declspec(dllimport) unsigned long OBJC_IVAR_$_Sub$nsstring;
-// CHECK: #pragma warning(disable:4273)
-// CHECK: __declspec(allocate(".objc_ivar$B")) extern "C" __declspec(dllexport) unsigned long int OBJC_IVAR_$_Sub$subIvar
-// CHECK: __declspec(allocate(".objc_ivar$B")) extern "C" __declspec(dllexport) unsigned long int OBJC_IVAR_$_Sub$nsstring
-// CHECK: __declspec(allocate(".objc_ivar$B")) extern "C" unsigned long int OBJC_IVAR_$_Sub$PrivateIvar
-// CHECK: extern "C" __declspec(dllimport) struct _class_t OBJC_METACLASS_$_NSObject;
-// CHECK: extern "C" __declspec(dllexport) struct _class_t OBJC_METACLASS_$_Sub
-// CHECK: extern "C" __declspec(dllimport) struct _class_t OBJC_CLASS_$_NSObject;
-// CHECK: extern "C" __declspec(dllexport) struct _class_t OBJC_CLASS_$_Sub
-// CHECK: extern "C" __declspec(dllexport) struct _class_t OBJC_CLASS_$_NSString;
-// CHECK: extern "C" __declspec(dllexport) struct _class_t OBJC_METACLASS_$_NSString
-// CHECK: extern "C" __declspec(dllexport) struct _class_t OBJC_CLASS_$_NSString