Remove not-needed stdio include from tests

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>

tests/suites/test_suite_alignment.function

@@ -6,7 +6,6 @@
 #if defined(__clang__)
 #pragma clang diagnostic ignored "-Wunreachable-code"
 #endif
-#include <stdio.h>
 
 /*
  * Convert a string of the form "abcd" (case-insensitive) to a uint64_t.

tests/suites/test_suite_constant_time.function

@@ -15,8 +15,6 @@
 #include <test/constant_flow.h>
 /* END_HEADER */
 
-#include <stdio.h>
-
 /* BEGIN_CASE */
 void mbedtls_ct_memcmp_null()
 {