GORM doesn't respect table schema mapping on table-per-subclass inherited domain classes

**Grails 3.1.1, against an Oracle database**

When mapping a table-per-subclass strategy with a schema specified, the schema is picked up by the superclass, but not by the subclass. See below.

**class A**

```
mapping= {
table(schema: 'WOOT', name 'A')
tablePerHierarchy(false)
}
```

**class B extends A**

```
mapping= {
table(schema: 'WOOT', name: 'B')
}
```

**B.read(1)** results in:
`Hibernate: select ... from B this_ inner join WOOT.A this_1_`
Class B _does not_ have the schema prepended in the SQL statement.

No repository file or test path is identified in the report. Start by reproducing the Grails 3.1.1 table-per-subclass mapping against Oracle, then trace the generated SQL for B.read(1); done means the subclass table is qualified with the WOOT schema like the superclass table.

Written by the indexing model from the issue text.