Add stage2 and other dependencies for check-glibc-linux

Some glibc tests like tst-unwind-{main,ctor} depends on stage2 artifacts
(in particular, GCC runtime libs) to be properly installed. Add stage2
dependencies to avoid these tests from spuriously failing.

The test suite also uses the simulator and Deja GNU, both of which were
not declared as dependencies, so add them as well.

Closes: https://github.com/riscv-collab/riscv-gnu-toolchain/issues/1379