There are better PRNGs than the one we chose when originally developing WiredTiger. Replace the current PRNG with xoshiro128**, then instead of seed it multiple times in the test programs, seed it once and then generate independent streams using the jump operator.

https://prng.di.unimi.it/

Note the page comment: "We suggest to use SplitMix64 to initialize the state of our generators starting from a 64-bit seed, as research has shown that initialization must be performed with a generator radically different in nature from the one initialized to avoid correlation on similar seeds."