Prefer EIP1271Verifier.isValidSignature.selector to static constant

Author: fedgiac

test/GPv2Signing/RecoverOrderSigner.t.sol

@@ -151,7 +151,7 @@ contract RecoverOrderSigner is Helper {
         bytes memory eip1271SignatureData = hex"";
 
         assertEq(evilVerifier.state(), 0);
-        assertEq(evilVerifier.isValidSignature(hash, eip1271SignatureData), Sign.EIP1271_MAGIC_VALUE);
+        assertEq(evilVerifier.isValidSignature(hash, eip1271SignatureData), EIP1271Verifier.isValidSignature.selector);
         assertEq(evilVerifier.state(), 1);
         vm.expectRevert();
         executor.recoverOrderSignerTest(

test/libraries/Sign.sol

@@ -16,8 +16,6 @@ library Sign {
 
     // Copied from GPv2Signing.sol
     uint256 internal constant PRE_SIGNED = uint256(keccak256("GPv2Signing.Scheme.PreSign"));
-    // As prescribed by EIP-1271
-    bytes4 internal constant EIP1271_MAGIC_VALUE = bytes4(keccak256("isValidSignature(bytes32,bytes)"));
 
     /// @dev A struct combining the signing scheme and the scheme's specific-encoded data
     struct Signature {