Changing Void to be annotated with @nullable and updating any other n…

…eeded types this should be a no-op for everything but J2KT.

This change will prevent J2KT from erroneously null!!.  This is valid because Void is always Nullable in Java (or the code can not execute).

RELNOTES=n/a
PiperOrigin-RevId: 714075337

android/guava/src/com/google/common/base/Suppliers.java

@@ -174,7 +174,7 @@ static class NonSerializableMemoizingSupplier<T extends @Nullable Object> implem
     private final Object lock = new Object();
 
     @SuppressWarnings("UnnecessaryLambda") // Must be a fixed singleton object
-    private static final Supplier<Void> SUCCESSFULLY_COMPUTED =
+    private static final Supplier<@Nullable Void> SUCCESSFULLY_COMPUTED =
         () -> {
           throw new IllegalStateException(); // Should never get called.
         };

guava/src/com/google/common/base/Suppliers.java

@@ -174,7 +174,7 @@ static class NonSerializableMemoizingSupplier<T extends @Nullable Object> implem
     private final Object lock = new Object();
 
     @SuppressWarnings("UnnecessaryLambda") // Must be a fixed singleton object
-    private static final Supplier<Void> SUCCESSFULLY_COMPUTED =
+    private static final Supplier<@Nullable Void> SUCCESSFULLY_COMPUTED =
         () -> {
           throw new IllegalStateException(); // Should never get called.
         };