Partially re-enable some @_objcImpl tests

These were disabled becuase they didn’t work properly in bots testing iOS or other platforms. Re-enable them for macOS until they can be fully repaired.

Author: beccadax

test/IRGen/objc_implementation.swift

@@ -1,4 +1,5 @@
-// REQUIRES: rdar101420862
+// Test doesn't pass on all platforms (rdar://101420862)
+// REQUIRES: OS=macosx
 
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -I %S/Inputs/abi -F %clang-importer-sdk-path/frameworks %s -import-objc-header %S/Inputs/objc_implementation.h -emit-ir > %t.ir
 // RUN: %FileCheck --input-file %t.ir %s

test/Interpreter/objc_implementation_swift_client.swift

@@ -1,4 +1,5 @@
-// REQUIRES: rdar101543397
+// Test doesn't pass on all platforms (rdar://101543397)
+// REQUIRES: OS=macosx
 
 //
 // Build objc_implementation.framework