nativeloader: Add CloseNativeLibrary() method

This method is called by art on UnloadNativeLibraries()

Bug: http://b/28406866
Change-Id: Ibccff93c83d6ccd3d0a1c0294a64b09281b4e05e
(cherry picked from commit 09a516bf161c5cabdaa3a67df5aa7fbac667f5f9)
2 files changed