Fix: AIX/Solaris use python3.8 in UT (#294)

Signed-off-by: Evgeny Malygin <[email protected]>

src/groups/mwc/mwcsys/mwcsys_executil.t.cpp

@@ -129,9 +129,19 @@ static void test2_executeSystemFailure()
     int         rc;
 
     PVV("Testing abnormal exit of the command");
+
+#if defined(BSLS_PLATFORM_OS_SOLARIS) || defined(BSLS_PLATFORM_OS_AIX)
+    // For AIX/Solaris, python2 support is stopped, and alias `python3`
+    // doesn't exist.  The final supported release is 3.8.
+    rc = mwcsys::ExecUtil::execute(&output,
+                                   "python3.8 -c 'import os,signal; "
+                                   "os.kill(os.getpid(), signal.SIGKILL)'");
+#else
     rc = mwcsys::ExecUtil::execute(&output,
                                    "python3 -c 'import os,signal; "
                                    "os.kill(os.getpid(), signal.SIGKILL)'");
+#endif
+
     ASSERT_EQ(rc, -2);
     ASSERT_EQ(output, "");