(1) Added -f <lib_name:func_name> parameter to parseThat.

(1) Added -f <lib_name:func_name> parameter to parseThat.
parseThat generates some simple instrumentation by default.
With -f parameter, user can specify a function in a library to
use as instrumentation. This will be useful to test binary
rewriter.

(2) Fix for test_thread_8 race condition.
test_thread_8 uses global variable sync_test and async_test to
pass the thread_id. If the order of thread execution changes, the
test fails. Hence, this test is broken. The thread_id must be passed as parameter to the function
and cannot be a global variable.