thread currently active (general BZ 233852).
- Enable back again the testcases named `attachstop.exp' (no such exist
now).
- Rename the testcase `gdb.threads/attachstop' to
`gdb.threads/attachstop-mt'.
- Test ia64 memory leaks of the code using libunwind.
- Testcase delay increase (for BZ 247354).
- Test gcore memory and time requirements for large inferiors.
