base: Revert 9277177eccff and use getenv/setenv for UTC time

This patch reverts changeset 9277177eccff which does not do what it
was intended to do. In essence, we go back to implementing mkutctime
much like the non-standard timegm extension.
sim: Sort SimObject descendants and ports

This patch fixes a number of occurences where the sorting order of the
objects was implementation defined.
arm: Fix timing wakeup with LLSC
mem: Delete unused variable in Garnet NetworkLink

With recent changes OSX clang compilation fails due to an unused variable.
stats: Bump regressions to match latest changes

Updates after timezone hick-up and sorting of dictionary items in the
SimObject.