Also, no vendored dependencies anymore, so we can fetch git
without submodules and use the libraries provided from
nix (flatbuffers, uhdm, gtest, antlr).
Update Surelog (going along with uhdm 1.45). Fix flaky tests
to to parallel execution of ctest by patching in a fix that is
already upstream.
Result zero hydra failures #199919
Also: using flatbuffers from nix environment instead of third_party/
Signed-off-by: Henner Zeller <h.zeller@acm.org>