GSHashTable: do not count duplicate keys when creating from an array

[DTW-Thalion]

Problem

GSHashTableCreate builds the table from the input array by calling GSHashTableAddKeyValuePair and incrementing _count for every element, with no check for a key that is already present:

bucket = GSHashTableFindBucket (new, keys[idx], _kGSHashTableInsert);
GSHashTableAddKeyValuePair (new, bucket, keys[idx], values[idx]);
new->_count += 1;

For a duplicate key, GSHashTableFindBucket returns the existing bucket, but _count is still incremented, so it ends up larger than the number of stored buckets. Since GSHashTableGetCount returns _count while GSHashTableGetKeysAndValues emits one entry per occupied bucket, the two disagree:

• CFSetGetCount / CFDictionaryGetCount over-report (e.g. CFSetCreate of {a, b, a} reports 3).
• CFSetGetValues (and the dictionary/bag equivalents) then read past the filled buckets into uninitialised memory.

This affects CFSetCreate, CFDictionaryCreate and CFBagCreate, which all share this path.

Fix

Guard the insert with the same bucket->count <= 0 check the mutable GSHashTableAddValue path already uses, so a key that is already present is not added or counted again. Creation now behaves consistently with incremental insertion.

Tests

Tests/CFSet/create_duplicates.m and Tests/CFDictionary/create_duplicates.m create a container from an array containing a repeated key and check the count. The dictionary test fails before this change (count 2) and passes after (count 1); both pass after the fix.