[libc][bit_test] fix -Wimplicit-int-conversion (#126317)
Fixes:
llvm-project/libc/src/__support/CPP/bit.h:235:28: error: implicit
conversion loses integer precision: 'int' to
'cpp::enable_if_t<cpp::is_unsigned_v<unsigned short>, unsigned short>'
(aka
'unsigned short') [-Werror,-Wimplicit-int-conversion]
235 | return (value << rotate) | (value >> (N - rotate));
| ~~~~~~ ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
llvm-project/libc/src/__support/CPP/bit.h:247:28: error: implicit
conversion loses integer precision: 'int' to
'cpp::enable_if_t<cpp::is_unsigned_v<unsigned short>, unsigned short>'
(aka
'unsigned short') [-Werror,-Wimplicit-int-conversion]
247 | return (value >> rotate) | (value << (N - rotate));
| ~~~~~~ ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
llvm-project/libc/test/src/__support/CPP/bit_test.cpp:45:36: error:
implicit conversion loses integer precision: 'int' to 'unsigned char'
[-Werror,-Wimplicit-int-conversion]
45 | EXPECT_FALSE(has_single_bit<T>(two_bits_value));
| ~~~~~~~~~~~~~~ ^~~~~~~~~~~~~~
Via the libc-cpp-utils-tests ninja target.
