cmocka future-proofing

Development versions of cmocka require the intmax_t and uintmax_t types to be defined by the time the test code includes the <cmocka.h> header. These types are defined in the <stdint.h> header, which is included by the <inttypes.h> header, which in turn is already explicitly included by some of the programs in the tests/ directory. Ensure all programs in that directory that include the <cmocka.h> header also include the <inttypes.h> header to future-proof the code while keeping the change set minimal and the resulting code consistent. Also prevent explicitly including the <stdint.h> header in those programs as it is included by the <inttypes.h> header.

Also fix some compiler warnings in ht_test and clean up a header file that we are not using in v9.19 any more.