Bring llquantize support into Dtrace.

Bryan Cantrill implemented the equivalent of semi-log graph
paper for Dtrace so llquantize will use one logarithmic and
one linear scale.

Special thanks to Mark Peek for providing fix to an
assertion and to Fabian Keill for testing the port.

Illumos Revision: 13355:15b74a2a9a9d

Reference:
https://www.illumos/issues/905

Obtained from: Illumos
Tested by: Fabian Keill, mp
MFC after: 4 days