Windows: do not set USE_32BIT_TIME_T for Heimdal
Windows: do not set USE_32BIT_TIME_T for Heimdal

Heimdal does not have any backward compatibility issues unlike
MIT.  There is no reason to restrict out interfaces to using
32-bit time of 32-bit Windows.  Our supported compilers default
to 64-bit time_t.  Use it.

Change-Id: I931c547841c17897d7d55a61459519cb99973385

madscientist159/heimdal,madscientist159/heimdal,madscientist159/heimdal,madscientist159/heimdal,madscientist159/heimdal,madscientist159/heimdal,madscientist159/heimdal