Fix crash when ALTER TABLE recreates indexes on partitions

The skip_build flag was not being passed correctly when recursing to
indexes on partitions, leading to attempts to rebuild indexes when they
were not yet ready to be rebuilt.

Reported-by: Rajkumar Raghuwanshi
Discussion: https://postgr.es/m/CAKcux6mxNCGsgATwf5CGMF8g4WSupCXicCVMeKUTuWbyxHOMsQ@mail.gmail.com

src/backend/commands/indexcmds.c

@@ -1033,7 +1033,7 @@ DefineIndex(Oid relationId,
 								indexRelationId,	/* this is our child */
 								createdConstraintId,
 								is_alter_table, check_rights, check_not_in_use,
-								false, quiet);
+								skip_build, quiet);
 				}
 
 				pfree(attmap);