Do better at UBSAN warning deduplication

[Lukáš Zaoral]

A scan of rsync produces a dozen of reports like this that only differ in the actual address:

Error: UBSAN_WARNING:
rsync-3.2.7/log.c:858:13: runtime error: member access within misaligned address 0xaaab1c1e94c4 for type 'struct file_struct', which requires 8 byte alignment
0xaaab1c1e94c4: note: pointer points here
#  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
#              ^
...

Error: UBSAN_WARNING:
rsync-3.2.7/log.c:858:13: runtime error: member access within misaligned address 0xaaab20a640cc for type 'struct file_struct', which requires 8 byte alignment
0xaaab20a640cc: note: pointer points here
#  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
#              ^
...