Revert "Revert "SDK: Add stdlib.h include to pull in abort() (backport #21700) (#21704)""

This reverts commit 402d72bc48.

sdk/bpf/c/inc/solana_sdk.h

@@ -699,6 +699,7 @@ uint64_t entrypoint(const uint8_t *input);
  * Stub functions when building tests
  */
 #include <stdio.h>
+#include <stdlib.h>
 void sol_log_(const char *s, uint64_t len) {
   printf("Program log: %s\n", s);
 }