Revert r352732: [libFuzzer] replace slow std::mt19937 with a much faster std::minstd_rand

This causes a failure on the following bot as well as our internal ones:

http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fuzzer/builds/23103

llvm-svn: 352747
GitOrigin-RevId: d778d4fdedbadb7a72a357e79dcbafdeec900044
1 file changed