message: [secp256k1] Remove a warning in multiset test
  Summary: The cast done is unsafe due to memory alignement constraints.
  Test Plan:
  ninja check-secp256k1
  Verify that the test passes and that the warning is gone.
  Reviewers: #bitcoin_abc, Fabien
diff: @@ -40,7 +40,8 @@ static void initdata(void) {
  int n,m;
  for(n=0; n < DATACOUNT; n++) {
  for(m=0; m < DATALEN/4; m++) {
  - ((uint32_t*) elements[n])[m] = secp256k1_rand32();
  + uint32_t x = secp256k1_rand32();
  + memcpy(&elements[n][m], &x, sizeof(x));
  }
  }
  