Add the profiling settings for tests explicit.

Many profiling related tests make assumptions on the profiling settings,
e.g. opt_prof is off by default, and prof_active is default on when opt_prof is
on.  However the default settings can be changed via --with-malloc-conf at build
time.  Fixing the tests by adding the assumed settings explicitly.

test/unit/prof_tctx.sh

@@ -1,5 +1,5 @@
 #!/bin/sh
 
 if [ "x${enable_prof}" = "x1" ] ; then
-  export MALLOC_CONF="prof:true,lg_prof_sample:0"
+  export MALLOC_CONF="prof:true,prof_active:true,lg_prof_sample:0"
 fi