Reland 21774: Generate KeyedLoadGeneric with Hydrogen

src/field-index.h

Index: src/field-index.h
diff --git a/src/field-index.h b/src/field-index.h
index d7707648572ca922d09428a1adcdf08d81eac4c3..0f77c8c57e4481299ed83bd6c469c4dea5d20353 100644
--- a/src/field-index.h
+++ b/src/field-index.h
@@ -26,9 +26,7 @@ class FieldIndex V8_FINAL {
   static FieldIndex ForLookupResult(const LookupResult* result);
   static FieldIndex ForDescriptor(Map* map, int descriptor_index);
   static FieldIndex ForLoadByFieldIndex(Map* map, int index);
-  static FieldIndex ForKeyedLookupCacheIndex(Map* map, int index) {
-    return ForPropertyIndex(map, index);
-  }
+  static FieldIndex ForKeyedLookupCacheIndex(Map* map, int index);
 
   bool is_inobject() const {
     return IsInObjectBits::decode(bit_field_);
@@ -75,9 +73,7 @@ class FieldIndex V8_FINAL {
     return is_double() ? (result | 1) : result;
   }
 
-  int GetKeyedLookupCacheIndex() const {
-    return property_index();
-  }
+  int GetKeyedLookupCacheIndex() const;
 
   int GetLoadFieldStubKey() const {
     return bit_field_ &