Pull set of semaphore into its own function.

Pull set of semaphore into its own function.

* tapsets.cxx (uprobe_derived_probe_group::emit_module_decls):  Move
sdt_sem_address from standalone to stap_uprobes.  Remove sdt_sem_tid.
In emitted function stap_uprobe_change_plus distinguish VM_EXEC/VM_WRITE
cases, use sdt_sem_address member, move setting of semaphores to new
emitted function stap_uprobe_change_semaphore_plus.
(stap_uprobe_process_found): Call stap_uprobe_change_semaphore_plus.
(stap_uprobe_mmap_found): Likewise.
* stap-postgres.stp (postgresrelease): New.  Sync to current upstream version.
* stap-tcl.sh:  Check if wget failed.
* stap-tcl.stp: Check for skipped probes.
* xulrunner.exp: Check if wget failed.