Stress test "benchmark"

[L3tum]

Some framework additions for individual benchmarks to support being run as stress tests on one or multiple cores.

Some features would be:

• Choosing benchmarks to run as stress test
• Choosing size of benchmarks
• Choosing benchmarks for different cores (e.g. AVX on Core0, SSE on Core1)
• Being able to stop the stress test at any time
• Collecting statistics of the stress test (e.g. calculations done or even errors spotted)