When UBSan was enabled and 'make test' was executed, the following
runtime error was observed:
libradamsa.c:26055:29: runtime error: left shift of 16777215 by 8 places cannot be represented in type 'int'
This issue was caused by a left shift operation on a signed integer.
The fix involved changing the integer literal to an unsigned integer by
adding a 'U' suffix, ensuring the left shift operation produces the
correct value without overflow.
Fixes: 8178f4df ("remove radamsa, add radamsa custom mutator")