Add a testcase for raise(SIGABRT).

tests/general/sigabrt.c

@@ -0,0 +1,11 @@
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+    fprintf("raising SIGABRT...\n");
+    raise(SIGABRT);
+    fprintf("oops!\n");
+    return EXIT_FAILURE;
+}

tests/general/sigabrt.c.exit_status.expected

@@ -0,0 +1 @@
+134

tests/general/sigabrt.c.options

@@ -0,0 +1 @@
+-D_WASI_EMULATED_SIGNAL -lwasi-emulated-signal

tests/general/sigabrt.c.stderr.expected

@@ -0,0 +1,7 @@
+raising SIGABRT...
+Error: failed to run main module `sigabrt.c.---.wasm`
+
+Caused by:
+    0: failed to invoke `_start`
+    1: wasm trap: unreachable, source location: @----
+       wasm backtrace:

tests/general/sigabrt.c.stderr.expected.filter

@@ -0,0 +1,7 @@
+#!/bin/bash
+set -euo pipefail
+
+cat \
+    | sed -e 's/main module `sigabrt\.c\.[^`]*\.wasm`/main module `sigabrt.c.---.wasm`/' \
+    | sed -e 's/source location: @[[:xdigit:]]*$/source location: @----/' \
+    | head -n 6