Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

DTrace: print() should try to resolve function pointers

Merge changes from illumos:

3675 DTrace print() should try to resolve function pointers
3676 dt_print_enum hardcodes a value of zero

Illumos Revision: b1fa6326238973aeaf12c34fcda75985b6c06be1

Reference:
https://www.illumos.org/issues/3675
https://www.illumos.org/issues/3676

Obtained from: Illumos
MFC after: 1 month

Update vendor/illumos/dist to illumos-gate 14004:dd91fed709a7

Illumos DTrace issues:
3675 DTrace print() should try to resolve function pointers
3676 dt_print_enum hardcodes a value of zero