Update the ioblock and scheduler tapsets and testcases.

Update the ioblock and scheduler tapsets and testcases.

* tapset/ioblock.stp: Fixed several problems where the ioblock_trace
  probes didn't all export the same convenience variables.  Works on
  RHEL4, RHEL5, RHEL6(beta), f11, f12, and rawhide.
* tapset/scheduler.stp: Fixed several problems where the kprobes backup
  probes for tracepoints didn't work.  Works on RHEL4, RHEL5, RHEL6(beta),
  f11, f12, and rawhide.
* testsuite/buildok/ioblock-all-probes.stp: New testcase.
* testsuite/buildok/ioblock-detailed.stp: New detailed test of all ioblock
  probes and convenience variables.
* testsuite/buildok/ioblock-embedded.stp: Added bio_rw_str() test.
* testsuite/buildok/ioblock_test.stp: Deleted old ioblock test.
* testsuite/buildok/scheduler-embedded.stp: New testcase.
* testsuite/buildok/scheduler-detailed.stp: New detailed test of all
  scheduler probes and convenience variables.
* testsuite/buildok/scheduler-cpu_off.stp: New detailed test which can
  fail on some platforms because we can't find inline function arguments.
* testsuite/buildok/scheduler-ctxswitch.stp: Ditto.
* testsuite/buildok/scheduler-migrate.stp: Ditto.
* testsuite/buildok/scheduler-test-tracepoints.stp: Deleted old test.
* testsuite/buildok/sched_test.stp: Ditto.
* testsuite/systemtap.pass1-4/buildok.exp: Kfail the scheduler
  single-probe tests.