rseq/selftests: Provide parametrized tests

"param_test" is a parametrizable restartable sequences test. See
the "--help" output for usage.

"param_test_benchmark" is the same as "param_test", but it removes
testing book-keeping code to allow accurate benchmarks.

"param_test_compare_twice" is the same as "param_test", but it performs
each comparison within rseq critical section twice, thus validating
invariants. If any of the second comparisons fails, an error message
is printed and the test aborts.

Signed-off-by: Mathieu Desnoyers <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Dave Watson <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: [email protected]
Cc: "H . Peter Anvin" <[email protected]>
Cc: Chris Lameter <[email protected]>
Cc: Russell King <[email protected]>
Cc: Andrew Hunter <[email protected]>
Cc: Michael Kerrisk <[email protected]>
Cc: "Paul E . McKenney" <[email protected]>
Cc: Paul Turner <[email protected]>
Cc: Boqun Feng <[email protected]>
Cc: Josh Triplett <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Ben Maurer <[email protected]>
Cc: [email protected]
Cc: Andy Lutomirski <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Linus Torvalds <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

Author: compudj