assert() games:

testmutexscope relies on assert() to check as well as to run at all,
so make sure NDEBUG isn't defined.

testpass and teststr don't use assert(), so don't include <assert.h>.


git-svn-id: https://svn.apache.org/repos/asf/apr/apr/trunk@1523479 13f79535-47bb-0310-9956-ffa450edef68