[test] Fix stdlib/Reflection_objc.swift with newer deployment target
This test stops working with deployment targets that no longer link
@rpath/libswiftCoreGraphics.dylib when running on OSes that still
require the CoreGraphics overlay. Explicitly link it to workaround.
(cherry picked from commit 081774ab07718dd086ffb0aa8868c61ecc825161)
(cherry picked from commit 8a4b2fddcd57058a1e506c6f1263d0f907dd4dd3)