Add test about invalid comparison with GMP objects

Also remove some dead code

Author: Girgias

ext/gmp/gmp.c

@@ -429,9 +429,7 @@ static int gmp_compare(zval *op1, zval *op2) /* {{{ */
 	zval result;
 
 	gmp_cmp(&result, op1, op2);
-	if (Z_TYPE(result) == IS_FALSE) {
-		return 1;
-	}
+	/* result can only be a zend_long if gmp_cmp hasn't thrown an Error */
 	return Z_LVAL(result);
 }
 /* }}} */

ext/gmp/tests/comparison_invalid.phpt

@@ -0,0 +1,23 @@
+--TEST--
+Overloaded GMP comparison in sort() etc
+--SKIPIF--
+<?php if (!extension_loaded("gmp")) print "skip"; ?>
+--FILE--
+<?php
+
+try {
+    var_dump("hapfegfbu" > gmp_init(0));
+} catch (\Error $e) {
+    echo $e::class, ': ', $e->getMessage(), \PHP_EOL;
+}
+
+try {
+    var_dump((new DateTime()) > gmp_init(0));
+} catch (\Error $e) {
+    echo $e::class, ': ', $e->getMessage(), \PHP_EOL;
+}
+
+?>
+--EXPECT--
+TypeError: main(): Argument #2 is not an integer string
+TypeError: main(): Argument #2 must be of type GMP|string|int, DateTime given