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/gc/accounting/heap_bitmap-inl.h b/runtime/gc/accounting/heap_bitmap-inl.h
index c67542f..34c15c7 100644
--- a/runtime/gc/accounting/heap_bitmap-inl.h
+++ b/runtime/gc/accounting/heap_bitmap-inl.h
@@ -40,9 +40,9 @@
   if (LIKELY(bitmap != nullptr)) {
     return bitmap->Test(obj);
   }
-  for (const auto& bitmap : large_object_bitmaps_) {
-    if (LIKELY(bitmap->HasAddress(obj))) {
-      return bitmap->Test(obj);
+  for (const auto& lo_bitmap : large_object_bitmaps_) {
+    if (LIKELY(lo_bitmap->HasAddress(obj))) {
+      return lo_bitmap->Test(obj);
     }
   }
   LOG(FATAL) << "Invalid object " << obj;
@@ -55,9 +55,9 @@
     bitmap->Clear(obj);
     return;
   }
-  for (const auto& bitmap : large_object_bitmaps_) {
-    if (LIKELY(bitmap->HasAddress(obj))) {
-      bitmap->Clear(obj);
+  for (const auto& lo_bitmap : large_object_bitmaps_) {
+    if (LIKELY(lo_bitmap->HasAddress(obj))) {
+      lo_bitmap->Clear(obj);
     }
   }
   LOG(FATAL) << "Invalid object " << obj;
@@ -70,9 +70,9 @@
     return bitmap->Set(obj);
   }
   visitor(obj);
-  for (const auto& bitmap : large_object_bitmaps_) {
-    if (LIKELY(bitmap->HasAddress(obj))) {
-      return bitmap->Set(obj);
+  for (const auto& lo_bitmap : large_object_bitmaps_) {
+    if (LIKELY(lo_bitmap->HasAddress(obj))) {
+      return lo_bitmap->Set(obj);
     }
   }
   LOG(FATAL) << "Invalid object " << obj;
@@ -87,9 +87,9 @@
     return bitmap->AtomicTestAndSet(obj);
   }
   visitor(obj);
-  for (const auto& bitmap : large_object_bitmaps_) {
-    if (LIKELY(bitmap->HasAddress(obj))) {
-      return bitmap->AtomicTestAndSet(obj);
+  for (const auto& lo_bitmap : large_object_bitmaps_) {
+    if (LIKELY(lo_bitmap->HasAddress(obj))) {
+      return lo_bitmap->AtomicTestAndSet(obj);
     }
   }
   LOG(FATAL) << "Invalid object " << obj;