Improve type printing of size-dependent const arrays to normalize array-of-const and const-array

Follow-on from 2bd84938 based on
postcommit feedback from Richard Smith.

The VariableArray case I couldn't figure out how to test/provoke - you
can't write/form a variable array in any context other than a local
variable that I know of, and in that case `const int x[n]` is the
normalized form already (array-of-const) and you can't use typedefs
(since you can't typedef int[n] with variable 'n') to force the
const-array AST that would produce the undesirable type printing "int
const [n]".