// asserts equality of the actual diff and expected diff
// considering datetime varitations
//
// It replaces the modification time in the actual diff
// with placeholder "TIMESTAMP" and then asserts the equality
//
// For eg.
// let brief = "*** fruits_old.txt\t2024-03-24 23:43:05.189597645 +0530\n
// --- fruits_new.txt\t2024-03-24 23:35:08.922581904 +0530\n";
//
// replaced = "*** fruits_old.txt\tTIMESTAMP\n
// --- fruits_new.txt\tTIMESTAMP\n";