Fix Wconversion in the tls* and api/test* files

[gasbytes]

Description

Fix issues related to -Wconversion and -Wsign-conversion in the tls* api/test* files.

[JacobBarthelmeh]

Having the proper casts is nice thanks, it's failing some CI tests though. Putting the assignee back to @gasbytes until resolved.

[dgarske]

@gasbytes

tests/api.c:73079:12: error: implicit conversion loses integer precision: 'unsigned long' to 'word32' (aka 'unsigned int') [-Werror,-Wshorten-64-to-32]
    return lh_strhash(s[3]);
    ~~~~~~ ^~~~~~~~~~~~~~~~
./wolfssl/openssl/lhash.h:55:29: note: expanded from macro 'lh_strhash'
#define lh_strhash          wolfSSL_LH_strhash
                            ^
1 error generated.