Dynamic builds should use --no-as-needed for executables, not just libraries

We currently add -Wl,--no-as-needed to SHLINKFLAGS, so that we don't silently drop library to library dependency edges if there is no symbolic dependency on platforms where -Wl,--no-as-needed is on by default. We don't want to drop those edges because even though there is no symbol level dependency, there may be a "hidden" dependency on static initializers or mongo initializers.

However, we have not done the same thing for executable to library edges, so we can still end up dropping a dependency edge.

We should add -Wl,--no-as-needed to LINKFLAGS instead of SHLINKFLAGS, so it is applied to both executables and dynamic libraries.