Disambiguate an ambiguous expression or type name.
(dimb-amb-expr/tyname expr/tyname table) → (mv erp expr-or-tyname new-table)
An ambiguous expression or type name is represented as a pair of an expression and a type name (with the same concrete syntax appearance). We attempt to disambiguate both the expression and the type name, independently from each other. In valid code, one of them must succeed and the other one must fail: then we disambiguate in favor of the one that succeeded. If none or both succeed, the code must be invalid.