Get some more debugging for ckati crashes

The crash we're following is likely a stack overflow. Use an alternate
stack to actually get the backtraces.

Also write out ulimit to reference what the stack size should be.

Bug: 36182021
Test: ulimit -s 768; build/soong/build_test.bash
Change-Id: I8826e5e53f38af552c8b80a1a8a490fde55f2d4b