message: Canonicalize timing outputs in logs 1.234 -> t.ttt
  Also, use ${SURELOG_DIR} instead of $(SURELOG_DIR) as the
  former could actually be used easier in shell expansions if that
  ever is requested.
diff: @@ -368,7 +368,8 @@ proc run_regression { } {
  set content [read $fid]
  close $fid
  # Canonicalize things that should be neutral in diff outputs
  - regsub -all {[a-zA-Z_/-]*/Surelog/} $content {$(SURELOG_DIR)/} content
  + regsub -all {[a-zA-Z_/-]*/Surelog/} $content {${SURELOG_DIR}/} content
  + regsub -all {[0-9]+\.[0-9]{3}([0-9]{3})?s?} $content {t.ttts} content
  set outfd [open "$testdir/${testname}.log" "w"]
  puts -nonewline $outfd $content
  close $outfd
  