Case field getter body not generated for fields ending with a space

## Compiler version

`main`

## Minimized code

```Scala
case class A(`a `: String)
```

## Output

```scala
Concrete method has no definition: DefDef(a ,List(List()),TypeTree[TypeRef(ThisType(TypeRef(NoPrefix,module class lang)),class String)],EmptyTree)
```

## Expectation

compile correctly
