tool_progress: fix large time outputs and decimal size display

Time output:

- was broken for really large times

- now uses spaces instead of --:--:--

- >99999y is now the largest shown time

- show HH:MM:SS as long as hours are fewer than 100

Size:

- made the decimal output always only use a single decimal

Test:

- Add test 1622 to verify these functions

Closes #20177

src/tool_progress.h

@@ -34,6 +34,13 @@ int xferinfo_cb(void *clientp,
 bool progress_meter(CURLM *multi,
                     struct curltime *start,
                     bool final);
+struct per_transfer;
 void progress_finalize(struct per_transfer *per);
 
+#ifdef UNITTESTS
+UNITTEST char *max5data(curl_off_t bytes, char *max5, size_t mlen);
+UNITTEST void time2str(char *r, size_t rlen, curl_off_t seconds);
+
+#endif
+
 #endif /* HEADER_CURL_TOOL_PROGRESS_H */