ART: Add operator == and != with nullptr to Handle

Get it in line with ObjPtr and prettify our code.

Test: m
Change-Id: I1322e2a9bc7a85d7f2441034a19bf4d807b81a0e
diff --git a/runtime/proxy_test.cc b/runtime/proxy_test.cc
index 1292a81..5748475 100644
--- a/runtime/proxy_test.cc
+++ b/runtime/proxy_test.cc
@@ -114,8 +114,8 @@
       class_linker_->FindClass(soa.Self(), "LInterfaces$I;", class_loader)));
   Handle<mirror::Class> J(hs.NewHandle(
       class_linker_->FindClass(soa.Self(), "LInterfaces$J;", class_loader)));
-  ASSERT_TRUE(I.Get() != nullptr);
-  ASSERT_TRUE(J.Get() != nullptr);
+  ASSERT_TRUE(I != nullptr);
+  ASSERT_TRUE(J != nullptr);
 
   std::vector<mirror::Class*> interfaces;
   interfaces.push_back(I.Get());
@@ -123,7 +123,7 @@
   Handle<mirror::Class> proxy_class(hs.NewHandle(
       GenerateProxyClass(soa, jclass_loader, "$Proxy1234", interfaces)));
   interfaces.clear();  // Don't least possibly stale objects in the array as good practice.
-  ASSERT_TRUE(proxy_class.Get() != nullptr);
+  ASSERT_TRUE(proxy_class != nullptr);
   ASSERT_TRUE(proxy_class->IsProxyClass());
   ASSERT_TRUE(proxy_class->IsInitialized());
 
@@ -148,8 +148,8 @@
       class_linker_->FindClass(soa.Self(), "LInterfaces$I;", class_loader)));
   Handle<mirror::Class> J(hs.NewHandle(
       class_linker_->FindClass(soa.Self(), "LInterfaces$J;", class_loader)));
-  ASSERT_TRUE(I.Get() != nullptr);
-  ASSERT_TRUE(J.Get() != nullptr);
+  ASSERT_TRUE(I != nullptr);
+  ASSERT_TRUE(J != nullptr);
 
   Handle<mirror::Class> proxyClass;
   {
@@ -159,7 +159,7 @@
     proxyClass = hs.NewHandle(GenerateProxyClass(soa, jclass_loader, "$Proxy1234", interfaces));
   }
 
-  ASSERT_TRUE(proxyClass.Get() != nullptr);
+  ASSERT_TRUE(proxyClass != nullptr);
   ASSERT_TRUE(proxyClass->IsProxyClass());
   ASSERT_TRUE(proxyClass->IsInitialized());
 
@@ -171,10 +171,10 @@
 
   Handle<mirror::Class> interfacesFieldClass(
       hs.NewHandle(class_linker_->FindSystemClass(soa.Self(), "[Ljava/lang/Class;")));
-  ASSERT_TRUE(interfacesFieldClass.Get() != nullptr);
+  ASSERT_TRUE(interfacesFieldClass != nullptr);
   Handle<mirror::Class> throwsFieldClass(
       hs.NewHandle(class_linker_->FindSystemClass(soa.Self(), "[[Ljava/lang/Class;")));
-  ASSERT_TRUE(throwsFieldClass.Get() != nullptr);
+  ASSERT_TRUE(throwsFieldClass != nullptr);
 
   // Test "Class[] interfaces" field.
   ArtField* field = &static_fields->At(0);
@@ -208,10 +208,10 @@
     proxyClass1 = hs.NewHandle(GenerateProxyClass(soa, jclass_loader, "$Proxy1", interfaces));
   }
 
-  ASSERT_TRUE(proxyClass0.Get() != nullptr);
+  ASSERT_TRUE(proxyClass0 != nullptr);
   ASSERT_TRUE(proxyClass0->IsProxyClass());
   ASSERT_TRUE(proxyClass0->IsInitialized());
-  ASSERT_TRUE(proxyClass1.Get() != nullptr);
+  ASSERT_TRUE(proxyClass1 != nullptr);
   ASSERT_TRUE(proxyClass1->IsProxyClass());
   ASSERT_TRUE(proxyClass1->IsInitialized());