[RFC PATCH-for-10.2? v2] tests/tcg: Skip syscall catchpoint test if pipe2() syscall not available

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

Avoid the following errors testing i386 and ppc64:

  $ make check-tcg
  ...
    TEST    hitting a syscall catchpoint on i386
  warning: File transfers from remote targets can be slow. Use "set sysroot" to access files locally instead.
  Traceback (most recent call last):
    File "tests/tcg/multiarch/gdbstub/catch-syscalls.py", line 53, in <module>
      main(run_test)
    File "tests/guest-debug/test_gdbstub.py", line 53, in main
      test()
    File "tests/tcg/multiarch/gdbstub/catch-syscalls.py", line 22, in run_test
      gdb.execute("catch syscall pipe2 read")
  gdb.error: Unknown syscall name 'pipe2'.
  qemu-i386: QEMU: Terminated via GDBstub
  ...
    TEST    hitting a syscall catchpoint on ppc64
  warning: File transfers from remote targets can be slow. Use "set sysroot" to access files locally instead.
  Traceback (most recent call last):
    File "tests/tcg/multiarch/gdbstub/catch-syscalls.py", line 53, in <module>
      main(run_test)
    File "tests/guest-debug/test_gdbstub.py", line 53, in main
      test()
    File "tests/tcg/multiarch/gdbstub/catch-syscalls.py", line 22, in run_test
      gdb.execute("catch syscall pipe2 read")
  gdb.error: Unknown syscall name 'pipe2'.
  qemu-ppc64: QEMU: Terminated via GDBstub
  ...
    TEST    hitting a syscall catchpoint on ppc64le
  warning: File transfers from remote targets can be slow. Use "set sysroot" to access files locally instead.
  Traceback (most recent call last):
    File "tests/tcg/multiarch/gdbstub/catch-syscalls.py", line 53, in <module>
      main(run_test)
    File "tests/guest-debug/test_gdbstub.py", line 53, in main
      test()
    File "tests/tcg/multiarch/gdbstub/catch-syscalls.py", line 22, in run_test
      gdb.execute("catch syscall pipe2 read")
  gdb.error: Unknown syscall name 'pipe2'.
  qemu-ppc64le: QEMU: Terminated via GDBstub
  make: Target 'check-tcg' not remade because of errors.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
RFC because I have no clue whether SYS_pipe2 should be present
    on these targets, I just want the CI to pass full green.

v2: Drop extraneous 'if'
---
 tests/tcg/multiarch/gdbstub/catch-syscalls.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tests/tcg/multiarch/gdbstub/catch-syscalls.py b/tests/tcg/multiarch/gdbstub/catch-syscalls.py
index ccce35902fb..79c8d532d1f 100644
--- a/tests/tcg/multiarch/gdbstub/catch-syscalls.py
+++ b/tests/tcg/multiarch/gdbstub/catch-syscalls.py
@@ -22,7 +22,8 @@ def run_test():
         gdb.execute("catch syscall pipe2 read")
     except gdb.error as exc:
         exc_str = str(exc)
-        if "not supported on this architecture" in exc_str:
+        if "not supported on this architecture" in exc_str \
+                or "Unknown syscall name 'pipe2'" in exc_str:
             print("SKIP: {}".format(exc_str))
             return
         raise
-- 
2.51.0