Add large payload bench

[SerafimArts]

Please note that the phplrt implementation doesn't build an AST, as I didn't want to touch original grammar, which adds about 10% to the speed.

The PR only highlights regression and instability in the PHPStan type parser with increasing input payload size, as @ondrejmirtes requested.

Results (~14x times slower):

phplrt4: 961.932ms
phpstan: 13,201.727ms

P.S. In case of size increase (~28x times slower):

// - for ($i = 0; $i < 1000; ++$i) {
// + for ($i = 0; $i < 2000; ++$i) {

phplrt4: 1,941.367ms
phpstan: 54,044.375ms

etc.