Don't use dlopen on host for already loaded oat files.

Because the behavior of dlopen on the host is different then the
target in that case, and it causes tests to fail.

Bug: 28826195

Change-Id: Id202bbac3318bade89a4133a9bcb1ee01e8b6182
diff --git a/runtime/base/mutex.cc b/runtime/base/mutex.cc
index 71b238b..6f689d7 100644
--- a/runtime/base/mutex.cc
+++ b/runtime/base/mutex.cc
@@ -49,7 +49,7 @@
 MutatorMutex* Locks::mutator_lock_ = nullptr;
 Mutex* Locks::profiler_lock_ = nullptr;
 ReaderWriterMutex* Locks::oat_file_manager_lock_ = nullptr;
-ReaderWriterMutex* Locks::oat_file_count_lock_ = nullptr;
+Mutex* Locks::host_dlopen_handles_lock_ = nullptr;
 Mutex* Locks::reference_processor_lock_ = nullptr;
 Mutex* Locks::reference_queue_cleared_references_lock_ = nullptr;
 Mutex* Locks::reference_queue_finalizer_references_lock_ = nullptr;
@@ -953,7 +953,7 @@
     DCHECK(deoptimization_lock_ != nullptr);
     DCHECK(heap_bitmap_lock_ != nullptr);
     DCHECK(oat_file_manager_lock_ != nullptr);
-    DCHECK(oat_file_count_lock_ != nullptr);
+    DCHECK(host_dlopen_handles_lock_ != nullptr);
     DCHECK(intern_table_lock_ != nullptr);
     DCHECK(jni_libraries_lock_ != nullptr);
     DCHECK(logging_lock_ != nullptr);
@@ -1042,9 +1042,9 @@
     DCHECK(oat_file_manager_lock_ == nullptr);
     oat_file_manager_lock_ = new ReaderWriterMutex("OatFile manager lock", current_lock_level);
 
-    UPDATE_CURRENT_LOCK_LEVEL(kOatFileCountLock);
-    DCHECK(oat_file_count_lock_ == nullptr);
-    oat_file_count_lock_ = new ReaderWriterMutex("OatFile count lock", current_lock_level);
+    UPDATE_CURRENT_LOCK_LEVEL(kHostDlOpenHandlesLock);
+    DCHECK(host_dlopen_handles_lock_ == nullptr);
+    host_dlopen_handles_lock_ = new Mutex("host dlopen handles lock", current_lock_level);
 
     UPDATE_CURRENT_LOCK_LEVEL(kInternTableLock);
     DCHECK(intern_table_lock_ == nullptr);