Fix shared libraries not being reported via Reporter

This CL topic fixes shared libraries not being reporter via Reporter.
This particular CL changes the BaseDexClassLoader.Reporter interface to
report ClassLoader context strings rather than ClassLoader instances.
These ClassLoader context strings are computed directly by the runtime
(see the changes within art in the same topic).

Test: atest libcore.dalvik.system.BaseDexClassLoaderTest
Bug: 148494302
Change-Id: I46d8d9105bbdefdd058711b74a841500671cc050
3 files changed