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/java_vm_ext.cc b/runtime/java_vm_ext.cc
index f2bda05..29dda88 100644
--- a/runtime/java_vm_ext.cc
+++ b/runtime/java_vm_ext.cc
@@ -235,8 +235,8 @@
   void* FindNativeMethod(ArtMethod* m, std::string& detail)
       REQUIRES(Locks::jni_libraries_lock_)
       REQUIRES_SHARED(Locks::mutator_lock_) {
-    std::string jni_short_name(JniShortName(m));
-    std::string jni_long_name(JniLongName(m));
+    std::string jni_short_name(m->JniShortName());
+    std::string jni_long_name(m->JniLongName());
     mirror::ClassLoader* const declaring_class_loader = m->GetDeclaringClass()->GetClassLoader();
     ScopedObjectAccessUnchecked soa(Thread::Current());
     void* const declaring_class_loader_allocator =
@@ -258,13 +258,13 @@
         fn = library->FindSymbol(jni_long_name, shorty);
       }
       if (fn != nullptr) {
-        VLOG(jni) << "[Found native code for " << PrettyMethod(m)
+        VLOG(jni) << "[Found native code for " << m->PrettyMethod()
                   << " in \"" << library->GetPath() << "\"]";
         return fn;
       }
     }
     detail += "No implementation found for ";
-    detail += PrettyMethod(m);
+    detail += m->PrettyMethod();
     detail += " (tried " + jni_short_name + " and " + jni_long_name + ")";
     LOG(ERROR) << detail;
     return nullptr;
@@ -471,7 +471,7 @@
   }
   // TODO: is this useful given that we're about to dump the calling thread's stack?
   if (current_method != nullptr) {
-    os << "\n    from " << PrettyMethod(current_method);
+    os << "\n    from " << current_method->PrettyMethod();
   }
   os << "\n";
   self->Dump(os);
@@ -904,7 +904,7 @@
   CHECK(m->IsNative());
   mirror::Class* c = m->GetDeclaringClass();
   // If this is a static method, it could be called before the class has been initialized.
-  CHECK(c->IsInitializing()) << c->GetStatus() << " " << PrettyMethod(m);
+  CHECK(c->IsInitializing()) << c->GetStatus() << " " << m->PrettyMethod();
   std::string detail;
   void* native_method;
   Thread* self = Thread::Current();