Mark BluetoothClass#getClassOfDevice as TestApi

This method is being used the Android Things instrumentation test apk.

Bug: 111654175
Test: tests pass
Change-Id: Id3fcd2d89789868e50048542fd1dfe25d9986103

api/test-current.txt

@@ -73,6 +73,14 @@ package android.app.usage {
 
 }
 
+package android.bluetooth {
+
+  public final class BluetoothClass implements android.os.Parcelable {
+    method public int getClassOfDevice();
+  }
+
+}
+
 package android.content {
 
   public abstract class ContentResolver {

core/java/android/bluetooth/BluetoothClass.java

@@ -16,6 +16,7 @@
 
 package android.bluetooth;
 
+import android.annotation.TestApi;
 import android.annotation.UnsupportedAppUsage;
 import android.os.Parcel;
 import android.os.Parcelable;
@@ -293,6 +294,7 @@ public final class BluetoothClass implements Parcelable {
      *
      * @hide
      */
+    @TestApi
     public int getClassOfDevice() {
         return mClass;
     }