Overloading of package should be disallowed

[jaehyun1ee]

The spec puts a side-note about overloading in 7.2.10.2. Extern Objects:

Notice that overloading of parsers, controls, or packages is not allowed.

However, issue3379-1.p4 and issue3379.p4 are accepted by the p4c frontend while they define an overloaded package type.

package mypackaget(mypt<t> t2);
package mypackaget(mypt<t> t1, mypt<t> t2);