git: openjdk/jdk: 8257708: Remove redundant unmodifiableSet wrapper from already immutable set returned by Collections.singleton

[Aleksey Shipilev]

Changeset: d08c612b
Author:    Andrey Turbanov <turbanoff at gmail.com>
Committer: Aleksey Shipilev <shade at openjdk.org>
Date:      2020-12-04 06:32:14 +0000
URL:       https://git.openjdk.java.net/jdk/commit/d08c612b

8257708: Remove redundant unmodifiableSet wrapper from already immutable set returned by Collections.singleton

Reviewed-by: shade, sspitsyn

! src/java.management/share/classes/java/lang/management/DefaultPlatformMBeanProvider.java
! src/jdk.management/share/classes/com/sun/management/internal/PlatformMBeanProviderImpl.java