Add a trap handler to the benchmark framework

[xThaid]

When an exception is thrown during the execution of benchmarks, we handle it in a custom trap handler and report it to the user. For example:

  1214.50ns INFO     cocotb.regression                  crc32 failed
                                                        Traceback (most recent call last):
                                                          File "/home/jurb/dev/repos/coreblocks/test/regression/cocotb.py", line 271, in _my_test
                                                            await function(dut, *args, **kwargs)
                                                          File "/home/jurb/dev/repos/coreblocks/test/regression/cocotb/benchmark_entrypoint.py", line 12, in _do_benchmark
                                                            await run_benchmark(CocotbSimulation(dut), benchmark_name)
                                                          File "/home/jurb/dev/repos/coreblocks/test/regression/benchmark.py", line 97, in run_benchmark
                                                            raise RuntimeError(
                                                        RuntimeError: An exception was thrown while executing the benchmark. mcause: ILLEGAL_INSTRUCTION, mepc: 0xb2

Previously mtvec was set to 0x0, so the program would just start over again and the information about the exception would be lost.

edit: updated the example error

Fixes #658

[github-actions[bot]]

Benchmarks summary

Performance benchmarks

aha-mont64	crc32	minver	nettle-sha256	nsichneu	slre	statemate	ud
▼ 0.417 (-0.001)	0.513 (0.000)	▼ 0.337 (-0.000)	▼ 0.655 (-0.000)	▲ 0.361 (+0.005)	▲ 0.290 (+0.000)	▼ 0.326 (-0.001)	▼ 0.431 (-0.001)

You can view all the metrics here.

Synthesis benchmarks (basic)

Device utilisation: (ECP5)	LUTs used as DFF: (ECP5)	LUTs used as carry: (ECP5)	LUTs used as ram: (ECP5)	Max clock frequency (Fmax)
▼ 24313 (-246)	5924 (0)	770 (0)	972 (0)	▼ 50 (-3)

Synthesis benchmarks (full)

Device utilisation: (ECP5)	LUTs used as DFF: (ECP5)	LUTs used as carry: (ECP5)	LUTs used as ram: (ECP5)	Max clock frequency (Fmax)
▲ 34143 (+3912)	9177 (0)	▼ 1944 (-32)	1152 (0)	▼ 36 (-5)