[native] Allow non power of two task concurrency for native execution

Native execution does not have this limitation. Similar to
task_writer_count.

Author: arhimondr

presto-main-base/src/main/java/com/facebook/presto/SystemSessionProperties.java

@@ -549,7 +549,7 @@ public SystemSessionProperties(
                         Integer.class,
                         taskManagerConfig.getTaskConcurrency(),
                         false,
-                        value -> validateValueIsPowerOfTwo(requireNonNull(value, "value is null"), TASK_CONCURRENCY),
+                        featuresConfig.isNativeExecutionEnabled() ? value -> validateIntegerValue(value, TASK_CONCURRENCY, 1, false) : value -> validateValueIsPowerOfTwo(requireNonNull(value, "value is null"), TASK_CONCURRENCY),
                         value -> value),
                 booleanProperty(
                         TASK_SHARE_INDEX_LOADING,

presto-main-base/src/main/java/com/facebook/presto/execution/TaskManagerConfig.java

@@ -18,7 +18,6 @@
 import com.facebook.airlift.configuration.DefunctConfig;
 import com.facebook.airlift.configuration.LegacyConfig;
 import com.facebook.presto.memory.HighMemoryTaskKillerStrategy;
-import com.facebook.presto.util.PowerOfTwo;
 import io.airlift.units.DataSize;
 import io.airlift.units.DataSize.Unit;
 import io.airlift.units.Duration;
@@ -486,7 +485,6 @@ public TaskManagerConfig setPartitionedWriterCount(Integer partitionedWriterCoun
     }
 
     @Min(1)
-    @PowerOfTwo
     public int getTaskConcurrency()
     {
         return taskConcurrency;