tests: call srand() with urandom data before fuzz pass.
tests: call srand() with urandom data before fuzz pass.

Also increase the number of passes.

mongodbinc-interns/libbson,4Second2None/libbson_tmp,ajdavis/libbson,mapr/libbson,remicollet/libbson,mongodbinc-interns/libbson,paulmelnikow/libbson,Machyne/libbson,4Second2None/libbson_tmp,mongodbinc-interns/libbson,alexeyvo/libbson,ksuarz/libbson,rayyang2000/libbson,rayyang2000/libbson,bjori/libbson,rcsanchez97/libbson,Machyne/libbson,jqk6/libbson,paulmelnikow/libbson,paulmelnikow/libbson,bjori/libbson,rayyang2000/libbson,remicollet/libbson,alexeyvo/libbson,bjori/libbson,derickr/libbson,Convey-Compliance/libbson,mapr/libbson,Convey-Compliance/libbson,jqk6/libbson,mongodbinc-interns/libbson,remicollet/libbson,jqk6/libbson,mongodb/libbson,mapr/libbson,Machyne/libbson,derickr/libbson,rcsanchez97/libbson,alexeyvo/libbson,derickr/libbson,ajdavis/libbson,paulmelnikow/libbson,jqk6/libbson,Convey-Compliance/libbson,ajdavis/libbson,rcsanchez97/libbson,ksuarz/libbson,ksuarz/libbson,4Second2None/libbson_tmp,derickr/libbson,paulmelnikow/libbson,mongodb/libbson,remicollet/libbson,Machyne/libbson,rayyang2000/libbson,mongodb/libbson,4Second2None/libbson_tmp