Fold in shared library runtime updates.

This brings the testsuite for druntime/Phobos as shared libraries
to the same level as when built against static libraries.
Travis CI: Run tests with BUILD_SHARED_LIBS=ON.
CMake: Build shared library Phobos test runner with --no-as-needed.

--as-needed seems to be on by default on Ubuntu 12.04 LTS
(GNU ld (GNU Binutils for Ubuntu) 2.22). This leads to
libphobos2-ldc-unittest.so not being linked it all, and thus
the modules to test not being found.