Catch all exceptions in SimulationManager::update_()

[clinssen]

In SimulationManager::update_(), exceptions in a thread-parallel context are caught and buffered, to be re-thrown later outside of the parallel context. However, the try..catch block involved only wrapped the Node::update() call, not any of the other code in SimulationManager::update_().

This came up because the following line should be "fail_butnocrash_or_die"; the "hard failure" (exception not handled; SLI interpreter process terminates) was not being caught by the test:

nest-simulator/testsuite/unittests/test_binary.sli

Line 170 in 0888491

} fail_or_die

This PR moves the try..catch block one level higher so it wraps all code in SimulationManager::update_().

[jougs]

Nice catch. Thanks for fixing.