Simple subtyping check
The number of dimensions for array types.
this is directly assignable to other if no coercion or casting is needed to convert this to other.
On the JVM, BOOL, BYTE, CHAR, SHORT, and INT are like Ints for the purposes of calculating the lub.
On the JVM, similar to isIntSizedType except that BOOL isn't integral while LONG is.
On the JVM, FLOAT and DOUBLE.
Is this type a category 2 type in JVM terms? (ie, is it LONG or DOUBLE?)