When enabling ASan SPARC testing as per PR #107405, 3 stack overflow
tests `FAIL` on Linux/sparc64:
```
AddressSanitizer-sparc-linux :: TestCases/Linux/stack-overflow-recovery-mode.cpp
AddressSanitizer-sparc-linux :: TestCases/Linux/stack-overflow-sigbus.cpp
AddressSanitizer-sparc-linux :: TestCases/Posix/stack-overflow.cpp
AddressSanitizer-sparc-linux-dynamic :: TestCases/Linux/stack-overflow-recovery-mode.cpp
AddressSanitizer-sparc-linux-dynamic :: TestCases/Linux/stack-overflow-sigbus.cpp
AddressSanitizer-sparc-linux-dynamic :: TestCases/Posix/stack-overflow.cpp
```
However, as detailed in Issue #109771, even a Linux equivalent of the
Solaris/sparcv9 fix (PR #109101) doesn't improve the situation.
Therefore this patch `XFAIL`s the tests until the root cause can be
figured out.
Tested on `sparc64-unknown-linux-gnu`, `sparcv9-sun-solaris2.11`, and
`x86_64-pc-linux-gnu`.