Improve the dynamic linker diagnostics.

Lose the pid, only show the name of the function (not its whole signature),
and include the name of the library we failed to load. (I hadn't noticed
that the library name was missing before because in Java we add that into
the UnsatisfiedLinkError detail message.)

The new output looks like this:

  Cannot load library: soinfo_relocate(linker.cpp:968): cannot locate symbol "__libc_malloc_default_dispatch" referenced by "libc_malloc_debug_leak.so"...

Change-Id: I3bb5c9780d9aaf3a9e4418ea55bc98122a81f80f