[flang] Fix problems building with shared libraries on Linux

Building with gcc 8 or 9 with shared libraries had linking
problems in test/evaluate. Fix those by adding FortranSemantics
to the library dependencies.

Original-commit: flang-compiler/f18@009b9ab171b4a9d9a3b7ca79f1d0c0b5d0ee7a8c
Reviewed-on: https://github.com/flang-compiler/f18/pull/639