[LibOS] tests: Fix missing/wrong return values from main()

LibOS/shim/test/inline/fork.c

@@ -16,5 +16,5 @@ int main(int argc, char** argv) {
     }
 
     shim_exit_group(0);
-    return 0;  // should not reach here.
+    return 1;  // should not reach here.
 }

LibOS/shim/test/inline/helloworld.c

@@ -3,5 +3,5 @@
 int main(int argc, char** argv) {
     shim_write(1, "Hello world\n", 12);
     shim_exit_group(0);
-    return 0;  // should not reach here.
+    return 1;  // should not reach here.
 }

LibOS/shim/test/inline/vfork.c

@@ -16,5 +16,5 @@ int main(int argc, char** argv) {
     }
 
     shim_exit_group(0);
-    return 0;  // should not reach here.
+    return 1;  // should not reach here.
 }

LibOS/shim/test/native/fs.c

@@ -19,4 +19,5 @@ int main() {
     }
 
     close(fd);
+    return 0;
 }

LibOS/shim/test/native/kill.c

@@ -33,7 +33,6 @@ int main(int argc, char** argv) {
             kill(parent_pid, SIGKILL);
 
         printf("[pid=%d|ppid=%d] Hello, Dad!\n", getpid(), getppid());
-        return 0;
     } else {
         struct timespec rem;
         rem.tv_sec  = kill_parent ? 60 : 1;
@@ -47,6 +46,6 @@ int main(int argc, char** argv) {
             kill(pid, SIGKILL);
 
         printf("[pid=%d|ppid=%d] Hello, Kid!\n", getpid(), getppid());
-        return 0;
     }
+    return 0;
 }

LibOS/shim/test/native/script.c

@@ -12,5 +12,5 @@ int main(int argc, const char** argv, const char** envp) {
     setenv("IN_EXECVE", "1", 1);
 
     execv(new_argv[0], new_argv);
-    return 0;
+    return 1;
 }

LibOS/shim/test/regression/exec.c

@@ -12,5 +12,5 @@ int main(int argc, const char** argv, const char** envp) {
     setenv("IN_EXECVE", "1", 1);
 
     execv(new_argv[0], new_argv);
-    return 0;
+    return 1;
 }

LibOS/shim/test/regression/proc-path.c

@@ -21,4 +21,5 @@ int main(int argc, char** argv) {
     } else {
         printf("proc path test failure\n");
     }
+    return 0;
 }

Pal/src/host/Linux-SGX/test-sgx.c

@@ -76,4 +76,5 @@ int main(int argc, char** argv) {
         native_cpuid(&eax, &ebx, &ecx, &edx);
         printf("eax: %x ebx: %x ecx: %x edx: %x\n", eax, ebx, ecx, edx);
     }
+    return 0;
 }