Revert "Check the result of Future.cancel() when cancelling the other branch of dynamic execution."

This reverts commit 5b95d91.

Author: larsrc-google

src/main/java/com/google/devtools/build/lib/actions/DynamicStrategyRegistry.java

@@ -34,10 +34,6 @@ enum DynamicMode {
     public String toString() {
       return name;
     }
-
-    public DynamicMode other() {
-      return this == REMOTE ? LOCAL : REMOTE;
-    }
   }
 
   /**

src/main/java/com/google/devtools/build/lib/dynamic/DynamicSpawnStrategy.java

@@ -166,17 +166,7 @@ private static void stopBranch(
                           spawn.getMnemonic(), strategyThatCancelled.get())));
         }
 
-        if (!branchToCancel.cancel(true)) {
-          // This can happen if the other branch is local under local_lockfree and has returned
-          // its result but not yet cancelled this branch, or if the other branch was already
-          // cancelled for other reasons.
-          if (!branchToCancel.isCancelled()) {
-            throw new DynamicInterruptedException(
-                String.format(
-                    "Execution of %s strategy stopped because %s strategy could not be cancelled",
-                    cancellingStrategy, cancellingStrategy.other()));
-          }
-        }
+        branchToCancel.cancel(true);
         branchDone.acquire();
       } else {
         throw new DynamicInterruptedException(