Remove mirror:: and ArtMethod deps in utils.{h,cc}

The latest chapter in the ongoing saga of attempting to dump a DEX
file without having to start a whole runtime instance.  This episode
finds us removing references to ArtMethod/ArtField/mirror.

One aspect of this change that I would like to call out specfically
is that the utils versions of the "Pretty*" functions all were written
to accept nullptr as an argument.  I have split these functions up as
follows:
1) an instance method, such as PrettyClass that obviously requires
this != nullptr.
2) a static method, that behaves the same way as the util method, but
calls the instance method if p != nullptr.
This requires using a full class qualifier for the static methods,
which isn't exactly beautiful.  I have tried to remove as many cases
as possible where it was clear p != nullptr.

Bug: 22322814
Test: test-art-host
Change-Id: I21adee3614aa697aa580cd1b86b72d9206e1cb24
diff --git a/runtime/gc/space/image_space.cc b/runtime/gc/space/image_space.cc
index e9c8b95..6035406 100644
--- a/runtime/gc/space/image_space.cc
+++ b/runtime/gc/space/image_space.cc
@@ -398,7 +398,7 @@
     CHECK_ALIGNED(current, kObjectAlignment);
     auto* obj = reinterpret_cast<mirror::Object*>(current);
     CHECK(obj->GetClass() != nullptr) << "Image object at address " << obj << " has null class";
-    CHECK(live_bitmap_->Test(obj)) << PrettyTypeOf(obj);
+    CHECK(live_bitmap_->Test(obj)) << obj->PrettyTypeOf();
     if (kUseBakerOrBrooksReadBarrier) {
       obj->AssertReadBarrierPointer();
     }