Delay adding sysroot path to module name in case of non absolute executable

Delay adding sysroot path to module name in case of non absolute executable

Current stap code adds sysroot prematurely for probes that specify non
absolute path name, i.e like "foo", so when find_executable called it
receives full path as <sysroot>/foo and find_executable does not search
PATH while applying sysroot.

Fix delays adding sysroot till path inside of sysroot is searched first.

Also fix missing sysroot addition in glob expansion case.