hg: jdk/sandbox: 8240975: Extend NativeLibraries to support explicit unloading

[chris.hegarty at oracle.com]

Changeset: ec23fc249e34
Author:    mchung
Date:      2020-03-23 09:05 -0700
URL:       https://hg.openjdk.java.net/jdk/sandbox/rev/ec23fc249e34

8240975: Extend NativeLibraries to support explicit unloading
Reviewed-by: alanb, mcimadamore

! src/java.base/share/classes/java/lang/ClassLoader.java
! src/java.base/share/classes/jdk/internal/loader/BootLoader.java
! src/java.base/share/classes/jdk/internal/loader/NativeLibraries.java
! src/java.base/share/classes/jdk/internal/loader/NativeLibrary.java
! src/java.base/share/native/libjava/NativeLibraries.c
+ test/jdk/jdk/internal/loader/NativeLibraries/Main.java
+ test/jdk/jdk/internal/loader/NativeLibraries/java.base/jdk/internal/loader/NativeLibrariesTest.java
+ test/jdk/jdk/internal/loader/NativeLibraries/libnativeLibrariesTest.c
+ test/jdk/jdk/internal/loader/NativeLibraries/p/Test.java