Fix JVM signatures involving multi-dimensional array types

Apparently ASM's Type#getElementType returns the type of the array even if it's
multi-dimensional, so the loop was incorrect

core/descriptors.runtime/src/org/jetbrains/kotlin/load/java/structure/reflect/reflectClassUtil.kt

@@ -46,7 +46,6 @@ public val Class<*>.desc: String
         if (this == Void.TYPE) return "V"
         // This is a clever exploitation of a format returned by Class.getName(): for arrays, it's almost an internal name,
         // but with '.' instead of '/'
-        // TODO: ensure there are tests on arrays of nested classes, multi-dimensional arrays, etc.
         return createArrayType().getName().substring(1).replace('.', '/')
     }