s_counter should still be defined on non-Linux

- s_counter still needs to be defined somewhere in
NO_HARDWARE_COUNTERS builds
other platform warning in codegen

- fix noisy compiler warning
Allow hhas files to set the MayUseVV flag

If the last parameter is '...', set the MayUseVV flag
redis fixes from github comments

- applying github comment fixes (thanks @staabm )
Disable tests that fail on contbuild

These tests now seem to fail deterministically on contbuild. Disable them until we figure out why.
Rewrite get using nvGet()

Profile data shows much heavier use of ArrayData::nvGet(),
nvGetCell(), and exists(), than get().  So rewrite get()
using nvGet().
fix print flag mismatch build warning on other platforms

- fix mismatch between %lu and uint64_t in printf flags
Fixes and improvements for type aliases

Replace NameDef with a new struct of runtime-resolved typedef
information.  This needs to include more than Class* or Typedef*,
because we might have nullable type aliases, or a non-nullable alias
to a nullable typedef, or vice versa.  Switch to the new
TypeAnnotation stuff in TypedefStatement instead of just strings so
support for this isn't weird (shapes are outside of this for now
though---see the hack in parser.cpp).  Also fixes support for type
aliases to mixed.