Always run asan ckati on the build servers

We're seeing some rare crashes that appear to be stack overflows. To get
better debugging, use the asan version of ckati when 'dist' is
specified.

Bug: 36182021
Test: m -j
Test: m -j dist
Test: make -j dist (w/o lunch)
Change-Id: Ic3a5590974bfd718bf1929355d344b5933ac1d4f