Add new tests dbregs_dr*_dont_inherit_lwp and improve i386 compat
Add new tests:
- dbregs_dr0_dont_inherit_lwp
- dbregs_dr1_dont_inherit_lwp
- dbregs_dr2_dont_inherit_lwp
- dbregs_dr3_dont_inherit_lwp
Fix memcmp(3) usage when comparing registers. Comparing with len is
incorrect as it should be len*sizeof(register) or just sizeof(registers).
Don't check for 16 Debug Registers, it's amd64 specific and not portable
to i386.
Don't compare registers before and after triggering a trap, it's a bug that
was hidden by incorrect usage of memcmp(3).
Sponsored by <The NetBSD Foundation>
UnifiedSplitRaw
