Add default template args to Heap::Alloc*Object*().

Namely kInstrumented=true and kCheckLargeObject=true.

This is a follow-up after
    https://android-review.googlesource.com/963693

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Change-Id: I6c23e76f90f1892382c3bb8c331d12437bc23f89
diff --git a/runtime/mirror/string-alloc-inl.h b/runtime/mirror/string-alloc-inl.h
index 32b6bb4..e2b0805 100644
--- a/runtime/mirror/string-alloc-inl.h
+++ b/runtime/mirror/string-alloc-inl.h
@@ -192,11 +192,11 @@
 
   gc::Heap* heap = runtime->GetHeap();
   return ObjPtr<String>::DownCast(
-      heap->AllocObjectWithAllocator<kIsInstrumented, true>(self,
-                                                            string_class,
-                                                            alloc_size,
-                                                            allocator_type,
-                                                            pre_fence_visitor));
+      heap->AllocObjectWithAllocator<kIsInstrumented>(self,
+                                                      string_class,
+                                                      alloc_size,
+                                                      allocator_type,
+                                                      pre_fence_visitor));
 }
 
 template <bool kIsInstrumented>