py/gc: Clean up usage of GC_ALLOC_FLAG_HAS_FINALISER flag.

The calls signature for gc_malloc was changed in
5ed578e5b4, without cleaning up existing
code on the rationale that the previous bool is automatically converted
to an int with the same meaning.

This commit goes back and cleans up existing invocations to make their
behavior more readable in a modern context.

Signed-off-by: Anson Mansfield <amansfield@mantaro.com>

ports/esp8266/posix_helpers.c

@@ -33,7 +33,7 @@
 // Functions for external libs like axTLS, BerkeleyDB, etc.
 
 void *malloc(size_t size) {
-    void *p = gc_alloc(size, false);
+    void *p = gc_alloc(size, 0);
     if (p == NULL) {
         // POSIX requires ENOMEM to be set in case of error
         errno = ENOMEM;