Add internal tests for WASI threads (#1963)

Add internal tests for WASI threads. These tests are run in addition to
the ones in the proposal:
https://github.com/WebAssembly/wasi-threads/tree/main/test/testsuite.

The purpose is to test additional and more complex scenarios.

core/iwasm/libraries/lib-wasi-threads/test/common.h

@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2022 Amazon.com Inc. or its affiliates. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <assert.h>
+#include <pthread.h>
+#include <stdbool.h>
+#include <unistd.h>
+
+#include "wasi_thread_start.h"
+
+typedef enum {
+    BLOCKING_TASK_BUSY_WAIT,
+    BLOCKING_TASK_ATOMIC_WAIT,
+    BLOCKING_TASK_POLL_ONEOFF
+} blocking_task_type_t;
+
+/* Parameter to change test behavior */
+static bool termination_by_trap;
+static bool termination_in_main_thread;
+static blocking_task_type_t blocking_task_type;
+
+#define TIMEOUT_SECONDS 10ll
+#define NUM_THREADS 3
+static pthread_barrier_t barrier;
+
+typedef struct {
+    start_args_t base;
+    bool throw_exception;
+} shared_t;
+
+void
+run_long_task()
+{
+    if (blocking_task_type == BLOCKING_TASK_BUSY_WAIT) {
+        for (int i = 0; i < TIMEOUT_SECONDS; i++)
+            sleep(1);
+    }
+    else if (blocking_task_type == BLOCKING_TASK_ATOMIC_WAIT) {
+        __builtin_wasm_memory_atomic_wait32(
+            0, 0, TIMEOUT_SECONDS * 1000 * 1000 * 1000);
+    }
+    else {
+        sleep(TIMEOUT_SECONDS);
+    }
+}
+
+void
+start_job()
+{
+    /* Wait for all threads (including the main thread) to be ready */
+    pthread_barrier_wait(&barrier);
+    run_long_task(); /* Task to be interrupted */
+    assert(false && "Thread termination test failed");
+}
+
+void
+terminate_process()
+{
+    /* Wait for all threads (including the main thread) to be ready */
+    pthread_barrier_wait(&barrier);
+
+    if (termination_by_trap)
+        __builtin_trap();
+    else
+        __wasi_proc_exit(33);
+}
+
+void
+__wasi_thread_start_C(int thread_id, int *start_arg)
+{
+    shared_t *data = (shared_t *)start_arg;
+
+    if (data->throw_exception) {
+        terminate_process();
+    }
+    else {
+        start_job();
+    }
+}
+
+void
+test_termination(bool trap, bool main, blocking_task_type_t task_type)
+{
+    termination_by_trap = trap;
+    termination_in_main_thread = main;
+    blocking_task_type = task_type;
+
+    int thread_id = -1, i;
+    shared_t data[NUM_THREADS] = { 0 };
+    assert(pthread_barrier_init(&barrier, NULL, NUM_THREADS + 1) == 0
+           && "Failed to init barrier");
+
+    for (i = 0; i < NUM_THREADS; i++) {
+        /* No graceful memory free to simplify the test */
+        assert(start_args_init(&data[i].base)
+               && "Failed to allocate thread's stack");
+    }
+
+    /* Create a thread that forces termination through trap or `proc_exit` */
+    data[0].throw_exception = !termination_in_main_thread;
+    thread_id = __wasi_thread_spawn(&data[0]);
+    assert(thread_id > 0 && "Failed to create thread");
+
+    /* Create two additional threads to test exception propagation */
+    data[1].throw_exception = false;
+    thread_id = __wasi_thread_spawn(&data[1]);
+    assert(thread_id > 0 && "Failed to create thread");
+    data[2].throw_exception = false;
+    thread_id = __wasi_thread_spawn(&data[2]);
+    assert(thread_id > 0 && "Failed to create thread");
+
+    if (termination_in_main_thread) {
+        terminate_process();
+    }
+    else {
+        start_job();
+    }
+}