Optimize array_diff() for long values

[mehmetcansahin]

Summary

This adds a fast path for array_diff() when all compared values are integers. Instead of converting values to temporary strings, the implementation builds an integer-keyed exclude map and copies values from the first array when they are not present in that map.

Mixed-type inputs still fall back to the existing generic implementation, preserving current comparison behavior.

Benchmark

$a = range(0, 200000);
$b = range(100000, 300000);

$start = microtime(true);
for ($i = 0; $i < 10; $i++) {
    array_diff($a, $b);
}
printf("%.3fs\n", microtime(true) - $start);

Before: ~0.12s, after: ~0.024s (~5x faster).

Tests

• make -j8
• ./sapi/cli/php run-tests.php -n -q ext/standard/tests/array/array_diff*.phpt (50/50 pass)

The new test covers integer values, negative values, min/max integers, duplicate values, key preservation, string fallback cases, multiple exclude arrays, references, and empty results.