git: openjdk/mobile: 8243596: ModuleLayer::parents should return an unmodifiable list

[duke]

Changeset: f6dda951
Author:    Alan Bateman <alanb at openjdk.org>
Date:      2020-05-07 14:44:09 +0000
URL:       https://git.openjdk.java.net/mobile/commit/f6dda951

8243596: ModuleLayer::parents should return an unmodifiable list

Reviewed-by: mchung

! src/java.base/share/classes/java/lang/ModuleLayer.java
! src/java.base/share/classes/java/lang/module/Configuration.java
! test/jdk/java/lang/ModuleLayer/BasicLayerTest.java
! test/jdk/java/lang/module/ConfigurationTest.java