[llvm-test-suite] bug in paq8p.cpp

If `catch` block is executed, then the return value of `paqmain` is still 0 (which is a bug). Hence, in `if (rc) return rc;` the `return rc;` is not executed (which is unexpected).

```c
int paqmain(int argc, char** argv) {
...
catch(const char* s) {
if (s) printf("%s\n", s);
// <= why no return 1 here ??
}
if (pause) {
printf("\nClose this window or press ENTER to continue...\n");
getchar();
}
return 0;
}

int main(int argc, char **argv)
{
#ifndef LLVM
return paqmain(argc, argv);
#else
int rc = 1;
/* there is lot of static data, need a clean state for decompress to work
* properly, so fork */
pid_t pid = fork();
if (pid == 0) {
/* compress files */
exit(paqmain(argc, argv));
} else if (pid == -1) {
perror("fork() failed");
exit(1);
}
wait(&rc);
if (rc)
return rc;
```

Locate paq8p.cpp in the llvm-test-suite and inspect paqmain, especially the catch block and its return path. Compare that behavior with main's rc handling and wait call. Done means failures from the catch block propagate as a nonzero result and the relevant test behavior remains correct.

Written by the indexing model from the issue text.