Move functions from psa_crypto_helpers.h to a .c file

[gilles-peskine-arm]

tests/include/test/psa_crypto_helpers.h contains function definitions. That's a remnant from when we didn't have tests/src/*.c and unit tests had to be compiled as a monolithic C file. It's a problem because merely including the header causes an unused-function warning. The header should contain only function declarations (or static inline function definitions, but the functions in that header don't need to be inline).

[YanivBir]

Hi, Can I work on it? @gilles-peskine-arm

[gilles-peskine-arm]

Hi @YanivBir , yes, if you're willing, we'd be grateful. No one is working on this at the moment.

[YanivBir]

Ok, I'm working on it