Upstream RV change broke compilation

See https://zivgitlab.uni-muenster.de/HPC2SE-Project/pacxx-rv2/-/jobs/13665

The error is:

/builds/HPC2SE-Project/pacxx-rv2/llvm/projects/pacxxrt/lib/native/transforms/SPMDVectorizer.cpp: In member function 'virtual bool {anonymous}::SPMDVectorizer::runOnModule(llvm::Module&)':
/builds/HPC2SE-Project/pacxx-rv2/llvm/projects/pacxxrt/lib/native/transforms/SPMDVectorizer.cpp:191:12: error: 'struct rv::Config' has no member named 'useSLEEF'
     config.useSLEEF = true;
            ^
/builds/HPC2SE-Project/pacxx-rv2/llvm/projects/pacxxrt/lib/native/transforms/SPMDVectorizer.cpp:198:50: error: too many arguments to function 'void rv::addSleefResolver(const rv::Config&, rv::PlatformInfo&)'
     rv::addSleefResolver(config, platformInfo, 35);
                                                  ^
In file included from /builds/HPC2SE-Project/pacxx-rv2/llvm/projects/pacxxrt/lib/native/transforms/SPMDVectorizer.cpp:39:0:
/builds/HPC2SE-Project/pacxx-rv2/llvm/projects/pacxxrt/../../tools/rv/include/rv/resolver/resolvers.h:12:8: note: declared here
   void addSleefResolver(const Config & config, PlatformInfo & platInfo);
        ^
make[2]: *** [projects/pacxxrt/CMakeFiles/PACXXTransforms.dir/lib/native/transforms/SPMDVectorizer.cpp.o] Error 1

• Upstream 556a59a8f5b1cdfc442a5de60d12d76028492927: Last working upstream commit appearing in a CI run.
• Upstream 44f2a4c48eb5ffa127c74e51daef6cfe0c66e71e: Probably working.
• Upstream 255b27fa06e4046f73ae2cc50c009737f0ccd7ef: probable culprit.
• Upstream e3431eca756ead153556576ccbae2a913729413f: Definitely broken, see the CI job up top.

TODO:

• Pin rv2 master to a working upstream commit (!13 (merged))
• Make an rv2 branch/MR to follow upstream master again (!14 (merged))
• Make a matching runtime branch/MR to fix the build failures (pacxx-runtime!43 (merged))