Remove @Beta from AsyncCallable, ListenableScheduledFuture, and ClosingFuture.

The former two are simple interfaces. `ClosingFuture` was meant to be `@Beta` for only one release :)

`ListenableScheduledFuture` was particularly silly to have as `@Beta` because it's the return type of `ListeningScheduledExecutorService`, from which we'd already removed `@Beta`.

`AsyncCallable` makes extra sense to remove from `@Beta` at the same time as `Futures.submit`, `submitAsync`, and `scheduleAsync` (CL 416093023).

RELNOTES=`util.concurrent`: Removed `@Beta` from `AsyncCallable`, `ListenableScheduledFuture`, and `ClosingFuture`.
PiperOrigin-RevId: 416302588

Author: cpovirk

android/guava/src/com/google/common/util/concurrent/AsyncCallable.java

@@ -14,7 +14,6 @@
 
 package com.google.common.util.concurrent;
 
-import com.google.common.annotations.Beta;
 import com.google.common.annotations.GwtCompatible;
 import java.util.concurrent.Future;
 import org.checkerframework.checker.nullness.qual.Nullable;
@@ -28,7 +27,6 @@
  *
  * @since 20.0
  */
-@Beta
 @GwtCompatible
 @ElementTypesAreNonnullByDefault
 public interface AsyncCallable<V extends @Nullable Object> {

android/guava/src/com/google/common/util/concurrent/ClosingFuture.java

@@ -36,7 +36,6 @@
 import static java.util.logging.Level.SEVERE;
 import static java.util.logging.Level.WARNING;
 
-import com.google.common.annotations.Beta;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Function;
 import com.google.common.collect.FluentIterable;
@@ -191,7 +190,6 @@
  * @since 30.0
  */
 // TODO(dpb): Consider reusing one CloseableList for the entire pipeline, modulo combinations.
-@Beta // @Beta for one release.
 @DoNotMock("Use ClosingFuture.from(Futures.immediate*Future)")
 @ElementTypesAreNonnullByDefault
 // TODO(dpb): GWT compatibility.

android/guava/src/com/google/common/util/concurrent/ListenableScheduledFuture.java

@@ -14,7 +14,6 @@
 
 package com.google.common.util.concurrent;
 
-import com.google.common.annotations.Beta;
 import com.google.common.annotations.GwtCompatible;
 import java.util.concurrent.ScheduledFuture;
 import org.checkerframework.checker.nullness.qual.Nullable;
@@ -25,7 +24,6 @@
  * @author Anthony Zana
  * @since 15.0
  */
-@Beta
 @GwtCompatible
 @ElementTypesAreNonnullByDefault
 public interface ListenableScheduledFuture<V extends @Nullable Object>

guava/src/com/google/common/util/concurrent/AsyncCallable.java

@@ -14,7 +14,6 @@
 
 package com.google.common.util.concurrent;
 
-import com.google.common.annotations.Beta;
 import com.google.common.annotations.GwtCompatible;
 import java.util.concurrent.Future;
 import org.checkerframework.checker.nullness.qual.Nullable;
@@ -28,7 +27,6 @@
  *
  * @since 20.0
  */
-@Beta
 @FunctionalInterface
 @GwtCompatible
 @ElementTypesAreNonnullByDefault

guava/src/com/google/common/util/concurrent/ClosingFuture.java

@@ -36,7 +36,6 @@
 import static java.util.logging.Level.SEVERE;
 import static java.util.logging.Level.WARNING;
 
-import com.google.common.annotations.Beta;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Function;
 import com.google.common.collect.FluentIterable;
@@ -190,7 +189,6 @@
  * @since 30.0
  */
 // TODO(dpb): Consider reusing one CloseableList for the entire pipeline, modulo combinations.
-@Beta // @Beta for one release.
 @DoNotMock("Use ClosingFuture.from(Futures.immediate*Future)")
 @ElementTypesAreNonnullByDefault
 // TODO(dpb): GWT compatibility.

guava/src/com/google/common/util/concurrent/ListenableScheduledFuture.java

@@ -14,7 +14,6 @@
 
 package com.google.common.util.concurrent;
 
-import com.google.common.annotations.Beta;
 import com.google.common.annotations.GwtCompatible;
 import java.util.concurrent.ScheduledFuture;
 import org.checkerframework.checker.nullness.qual.Nullable;
@@ -25,7 +24,6 @@
  * @author Anthony Zana
  * @since 15.0
  */
-@Beta
 @GwtCompatible
 @ElementTypesAreNonnullByDefault
 public interface ListenableScheduledFuture<V extends @Nullable Object>