[ruby/prism] Correct constant pool bucket type logic

When replacing an owned constant by a different type (constant or
shared) replace with the correct type instead of defaulting to
shared.

ruby/prism@fbe9b131a1

Author: kddnewton

prism/util/pm_constant_pool.c

@@ -264,7 +264,7 @@ pm_constant_pool_insert(pm_constant_pool_t *pool, const uint8_t *start, size_t l
                 // constant and replace it with the shared constant.
                 xfree((void *) constant->start);
                 constant->start = start;
-                bucket->type = (unsigned int) (PM_CONSTANT_POOL_BUCKET_DEFAULT & 0x3);
+                bucket->type = (unsigned int) (type & 0x3);
             }
 
             return bucket->id;