Split lvalPtr() into createLvalPtr/getLvalPtr()

Callers are always passing a constant to choose one or the other,
so make them distinct methods.

hphp/runtime/base/array/array_data.cpp

@@ -194,9 +194,12 @@ bool ArrayData::equal(const ArrayData *v2, bool strict) const {
   return true;
 }
 
-ArrayData *ArrayData::lvalPtr(StringData* k, Variant *&ret, bool copy,
-                              bool create) {
-  throw FatalErrorException("Unimplemented ArrayData::lvalPtr");
+ArrayData *ArrayData::createLvalPtr(StringData* k, Variant *&ret, bool copy) {
+  throw FatalErrorException("Unimplemented ArrayData::createLvalPtr");
+}
+
+ArrayData *ArrayData::getLvalPtr(StringData* k, Variant *&ret, bool copy) {
+  throw FatalErrorException("Unimplemented ArrayData::getLvalPtr");
 }
 
 ArrayData *ArrayData::add(int64_t k, CVarRef v, bool copy) {