Fix/suppress binder google-explicit-constructor warnings

* Add explicit to conversion constructors/operators
* Use NOLINT or NOLINTNEXTLINE to suppress warnings on intended converters
* Remove redundant explicit of copy constructors

Bug: 28341362
Test: make with WITH_TIDY=1 DEFAULT_GLOBAL_TIDY_CHECKS=-*,google-explicit-constructor
Change-Id: If74d738496c5787c0ec68ff808801c7ff44cf03f
diff --git a/libs/binder/ndk/include_ndk/android/binder_auto_utils.h b/libs/binder/ndk/include_ndk/android/binder_auto_utils.h
index ff1860e..80773f3 100644
--- a/libs/binder/ndk/include_ndk/android/binder_auto_utils.h
+++ b/libs/binder/ndk/include_ndk/android/binder_auto_utils.h
@@ -51,7 +51,7 @@
      * Convenience operator for implicitly constructing an SpAIBinder from nullptr. This is not
      * explicit because it is not taking ownership of anything.
      */
-    SpAIBinder(std::nullptr_t) : SpAIBinder() {}
+    SpAIBinder(std::nullptr_t) : SpAIBinder() {}  // NOLINT(google-explicit-constructor)
 
     /**
      * This will delete the underlying object if it exists. See operator=.