Distribution of safe primes generated using different techniques
$\{p \in \mathbb Z \mid \text{$p$ is prime and $(p - 1)/2$ is prime}\} = \{2q + 1 \in \mathbb Z \mid \text{$q$ is prime and $2q + 1$ is prime}\}$

With your intervals suitably adjusted, the algorithm considers the same candidates with the same probability whether you check $p$ or $q$ for primality first.