Merge #14513: Avoid 1 << 31 (UB) in calculation of SEQUENCE_LOCKTIME_DISABLE_FLAG

bc60c61 Avoid 1 << 31 (UB) in calculation of SEQUENCE_LOCKTIME_DISABLE_FLAG (practicalswift)

Pull request description:

  Avoid `1 << 31` (UB) in calculation of `SEQUENCE_LOCKTIME_DISABLE_FLAG`.

  Context: bitcoin/bitcoin#14510 (comment)

Tree-SHA512: bdb4a913c6a82ff1a455ba67d3351f6408ff4116574329361644b483fea96b801fdc5c5659233856b591cd3a46ec669d3b5b438553e4240d7099c560eae2e2ae

Author: sipa

src/primitives/transaction.h

@@ -73,7 +73,7 @@ class CTxIn
     /* Below flags apply in the context of BIP 68*/
     /* If this flag set, CTxIn::nSequence is NOT interpreted as a
      * relative lock-time. */
-    static const uint32_t SEQUENCE_LOCKTIME_DISABLE_FLAG = (1 << 31);
+    static const uint32_t SEQUENCE_LOCKTIME_DISABLE_FLAG = (1U << 31);
 
     /* If CTxIn::nSequence encodes a relative lock-time and this flag
      * is set, the relative lock-time has units of 512 seconds,