[clang] [flang] [flang][Driver] Enable -pie and -no-pie in flang's driver (PR #164890)

[Tarun Prabhu via cfe-commits]

tarunprabhu wrote:

Per @MaskRay's comment, I have changed the name of `flang/test/Driver/misc-flags.f90` to `flang/test/Driver/linker-options.f90`. There is another test in `flang/test/Driver` named `linker-flags.f90`. Looking at the contents of that file, I think renaming it `link-libs.f90` would be good. However, since that is unrelated, it is not done in this PR.

https://github.com/llvm/llvm-project/pull/164890