Now, the gem5 implementation equals the Bochs variant. Note that it's
*not* necessary to enable CONFIG_EVENTS_BREAKPOINTS_RANGE in order to
use range breakpoints.
In addition, gem5 distinguishes between macro- and microops. With the
new implementation, onBreakpoint() is only called when a macroop
changes.

Change-Id: Ib86d1802fc70c20d22ca1a1ece0e8d1221b2e7db