asn1_test: Use the grub-specific functions and types

asn1_test: Use the grub-specific functions and types

This commit converts functions and types to the grub-specific ones:
  - LONG_MAX -> GRUB_LONG_MAX,
  - INT_MAX -> GRUB_INT_MAX,
  - UINT_MAX -> GRUB_UINT_MAX,
  - size_t -> grub_size_t,
  - memcmp() -> grub_memcmp(),
  - memcpy() -> grub_memcpy(),
  - free() -> grub_free(),
  - strcmp() -> grub_strcmp().

Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>