vclock: fix ub sanitizer warnings of int shifting by 31 bits

Caught the following error with UB sanitizer after trying to use the
31-st vclock component in one of the tests:

NO_WRAP
```
[040] +/opt/actions-runner/_work/tarantool/tarantool/src/lib/vclock/vclock.c:133:21: runtime error: left shift of 1 by 31 places cannot be represented in type 'int'
[040] +SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /opt/actions-runner/_work/tarantool/tarantool/src/lib/vclock/vclock.c:133:21 in
[040] Test "unit/vclock.test", conf: "None"
[040] 	failed, rerunning ...
[040] unit/vclock.test                                                [ fail ]
```
NO_WRAP

Let's fix this in all the affected places.

NO_DOC=refactoring
NO_TEST=already tested by unit/vclock.cc: test_minmax_ignore0()
NO_CHANGELOG=refactoring