Add tests

Author: Daniel-Cortez

source/compiler/tests/gh_525.meta

@@ -0,0 +1,6 @@
+{
+  'test_type': 'output_check',
+  'errors': """
+gh_525.pwn(1) : error 001: expected token: "=", but found ";"
+  """
+}

source/compiler/tests/gh_525.pwn

@@ -0,0 +1,8 @@
+native Tag:operator+(Tag:a, Tag:b); // error 001: expected token: "=", but found ";"
+
+// Make sure that valid native operator and function declarations aren't affected
+native Tag2:operator+(Tag2:a, Tag2:b) = NativeFunc;
+native Tag2:NativeFunc(Tag2:a, Tag2:b);
+native NativeFunc2(a,b) = NativeFunc;
+
+main(){}