[test] Add regression test for miscompilation

test/rt/x86-64-linux/zreadlink0.v3

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+def LOOKUP_SYMLINK_FOLLOW = 1;	// flag indicating should follow symlinks
+def SYS_readlink = 0x59;	// Linux system call to read a symlink
+def PATH_MAX = 15;		// maximum length of a path
+def EINVAL = 22;		// errno for invalid argument
+def ENOENT = 2;			// errno for no entry
+
+
+// Resolves a path without following symlinks, ensuring it stays within the sandbox.
+def resolve_path_without_link(path: string) -> (string, int) {
+	return (path, 0);
+}
+
+// Main function to resolve a path with an option to follow symlinks, ensuring it stays within the sandbox.
+def resolve_path0(fdpath: string, path: string, flags: i32) -> (string, int) {
+	var result = resolve_path_without_link(path);
+	if (result.1 != 0) return (result.0, result.1);
+	var normalized = result.0;
+
+	if ((flags & LOOKUP_SYMLINK_FOLLOW) == LOOKUP_SYMLINK_FOLLOW) {
+		var buffer = string.new(PATH_MAX);
+		var t = Linux.syscall(SYS_readlink, (Pointer.atContents(normalized), Pointer.atContents(buffer), PATH_MAX));
+
+		if (t.0 < 0) return (normalized, 0);
+		return (buffer, 0); // If the path is a symlink, return it
+	}
+	return (normalized, 0);
+}
+
+def main() -> int {
+	System.puts("##+resolve_path\n");
+	var expected = "/foo/test_path";
+	var result = resolve_path0("/foo", "/foo/test_path", 0).0;
+	if (expected == null) {
+		System.puts("##-fail, expected is null");
+	} else if (result == null) {
+		System.puts("##-fail, result is null");
+	} else if (!equal(expected, result)) {
+		System.puts("##-fail, got: ");
+		System.puts(result);
+	} else {
+		System.puts("##-ok\n");
+		return 0;
+	}
+	return 1;
+}
+
+// Compare two strings for equality.
+def equal(arr1: string, arr2: string) -> bool {
+	if (arr1 == arr2) return true;
+	if (arr1.length != arr2.length) return false;
+	for (i < arr1.length) {
+		if (arr1[i] != arr2[i]) return false;
+	}
+	return true;
+}

test/rt/x86-64-linux/zreadlink0.v3.exit

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+0

test/rt/x86-64-linux/zreadlink0.v3.out

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+##+resolve_path
+##-ok