This patch prevents jsfunfuzz logs from being cut off when ./testkjs crashes or hits an assertion failure. Since the tail end of the log is essential for reproducing the bug, having it not be cut off is good :) Fwiw, I made an equivalent patch for SpiderMonkey and it was accepted (see https://bugzilla.mozilla.org/show_bug.cgi?id=423042).
Created attachment 19880 [details] patch
r31229