ART: More warnings

Enable -Wno-conversion-null, -Wredundant-decls and -Wshadow in general,
and -Wunused-but-set-parameter for GCC builds.

Change-Id: I81bbdd762213444673c65d85edae594a523836e5
diff --git a/runtime/class_linker_test.cc b/runtime/class_linker_test.cc
index 88e6265..70807da 100644
--- a/runtime/class_linker_test.cc
+++ b/runtime/class_linker_test.cc
@@ -374,8 +374,8 @@
 
 template <typename T>
 struct CheckOffsets {
-  CheckOffsets(bool is_static, const char* class_descriptor)
-      : is_static(is_static), class_descriptor(class_descriptor) {}
+  CheckOffsets(bool is_static_in, const char* class_descriptor_in)
+      : is_static(is_static_in), class_descriptor(class_descriptor_in) {}
   bool is_static;
   std::string class_descriptor;
   std::vector<CheckOffset> offsets;