Issue #28727: Fix typo in pattern_richcompare()

Typo catched by Serhiy Storchaka, thanks!
diff --git a/Modules/_sre.c b/Modules/_sre.c
index c1e9fa6..1b77416 100644
--- a/Modules/_sre.c
+++ b/Modules/_sre.c
@@ -2688,7 +2688,7 @@
 
     cmp = (left->flags == right->flags
            && left->isbytes == right->isbytes
-           && left->codesize && right->codesize);
+           && left->codesize == right->codesize);
     if (cmp) {
         /* Compare the code and the pattern because the same pattern can
            produce different codes depending on the locale used to compile the