The parseok/semko.stp test case is really a shell script that tries to parse all the semko test files, to ensure that it is semantic (elaboration) checks that fail, not parse errors. So, it runs 'stap -p1' on all the semko tests. But, this isn't quite enough and the test always fails. Here's the tail of systemtap.log:

====
parse error: embedded expression code in unprivileged script; need stap -g
        saw: embedded-code at /root/rhel6/testsuite/../../src.copy/testsuite/../testsuite/semko/global_access.stp:8:11
     source:   println(%{ /* pragma:read:var */ STAP_GLOBAL_GET_var() %})
                       ^^
====

So, the test fails because semko/global_access.stp needs '-g', not because the script can't be parsed. In addition, the test appears to stop on the first failure, instead of checking the rest of the semko scripts.