Running unittests/Support/DynamicLibrary/DynamicLibraryTests fails
when LLVM is configured with -DLLVM_EXPORT_SYMBOLS_FOR_PLUGINS=ON, because
the test's version script only contains symbols extracted from the static libraries,
that the test links with, but not those from the main object/executable itself.
The patch moves the one symbol, needed by the test, to its own static library.