Merge bitcoin-core/secp256k1#1247: Apply Checks only in VERIFY mode.

4ebd828 Apply Checks only in VERIFY mode. (roconnor-blockstream)

Pull request description:

  This is already done in `field_5x52_impl.h`.

ACKs for top commit:
  sipa:
    ACK 4ebd828
  jonasnick:
    ACK 4ebd828

Tree-SHA512: c24211e5219907e41e2c5792255734bd50ca5866a4863abbb3ec174ed92d1792dd10563a94c08e8fecd6cdf776a9c49ca87e8f9806a023d9081ecc0d55ae3e66

Author: sipa

src/field_10x26_impl.h

@@ -1363,7 +1363,9 @@ static void secp256k1_fe_inv(secp256k1_fe *r, const secp256k1_fe *x) {
     secp256k1_modinv32(&s, &secp256k1_const_modinfo_fe);
     secp256k1_fe_from_signed30(r, &s);
 
+#ifdef VERIFY
     VERIFY_CHECK(secp256k1_fe_normalizes_to_zero(r) == secp256k1_fe_normalizes_to_zero(&tmp));
+#endif
 }
 
 static void secp256k1_fe_inv_var(secp256k1_fe *r, const secp256k1_fe *x) {
@@ -1376,7 +1378,9 @@ static void secp256k1_fe_inv_var(secp256k1_fe *r, const secp256k1_fe *x) {
     secp256k1_modinv32_var(&s, &secp256k1_const_modinfo_fe);
     secp256k1_fe_from_signed30(r, &s);
 
+#ifdef VERIFY
     VERIFY_CHECK(secp256k1_fe_normalizes_to_zero(r) == secp256k1_fe_normalizes_to_zero(&tmp));
+#endif
 }
 
 static int secp256k1_fe_is_square_var(const secp256k1_fe *x) {