Fix: BinExpr.isBasicComparison as attribute, not method

compiler/teal0/frontend/NullnessDataFlow.jrag

@@ -436,7 +436,7 @@ aspect BasicComparison {
 	 * - getBasicComparisonConstant()
 	 */
 	syn boolean Expr.isBasicComparison() = false;
-	public boolean BinExpr.isBasicComparison() {
+	eq BinExpr.isBasicComparison() {
 		return getBasicComparisonVar() != null
 		    && getBasicComparisonConstant() != null
 		    && isComparison();