[Driver] Fix -r handling on Solaris (#70322)

As discussed in [[Driver] Link Flang runtime on Solaris](https://github.com/llvm/llvm-project/pull/65644), `clang -r`
incorrectly passes both `-Bdynamic` and `-e _start` to `ld` which lets the linker choke.

This patch fixes this, omitting `-Bdynamic` completely which is the linker default.

Tested on `amd64-pc-solaris2.11` and `sparcv9-sun-solaris2.11`.