[runtime] Remove specific Descriptor subclasses and add respective factory methods instead.

test/cctest/heap/test-alloc.cc

Index: test/cctest/heap/test-alloc.cc
diff --git a/test/cctest/heap/test-alloc.cc b/test/cctest/heap/test-alloc.cc
index d7031e876d867b78de0585ff9a312ac60323ab3c..d69b6579584f11be6aba926c2a7ec598f1d1f4e8 100644
--- a/test/cctest/heap/test-alloc.cc
+++ b/test/cctest/heap/test-alloc.cc
@@ -154,8 +154,8 @@ TEST(StressJS) {
   Handle<AccessorInfo> foreign = TestAccessorInfo(isolate, attrs);
   Map::EnsureDescriptorSlack(map, 1);
 
-  AccessorConstantDescriptor d(Handle<Name>(Name::cast(foreign->name())),
-                               foreign, attrs);
+  Descriptor d = Descriptor::AccessorConstant(
+      Handle<Name>(Name::cast(foreign->name())), foreign, attrs);
   map->AppendDescriptor(&d);
 
   // Add the Foo constructor the global object.