Calculates the SLL(1) expected lookahead set for each outgoing transition
if an {@link ATNState}. The returned array has one element for each
outgoing transition in {@code s}. If the closure from transition
<em>i</em> leads to a semantic predicate before matching a symbol, the
element at index <em>i</em> of the result will be {@code null}.
@param s the ATN state
@return the expected symbols for each outgoing transition of {@code s}.
Calculates the SLL(1) expected lookahead set for each outgoing transition if an {@link ATNState}. The returned array has one element for each outgoing transition in {@code s}. If the closure from transition <em>i</em> leads to a semantic predicate before matching a symbol, the element at index <em>i</em> of the result will be {@code null}.
@param s the ATN state @return the expected symbols for each outgoing transition of {@code s}.