js: os now compiles to the JS backend, more builtins & minor codegen fixes (#11302)

vlib/os/os.c.v

@@ -0,0 +1,21 @@
+module os
+
+// write_file_array writes the data in `buffer` to a file in `path`.
+pub fn write_file_array(path string, buffer array) ? {
+	mut f := create(path) ?
+	unsafe { f.write_full_buffer(buffer.data, size_t(buffer.len * buffer.element_size)) ? }
+	f.close()
+}
+
+pub fn glob(patterns ...string) ?[]string {
+	mut matches := []string{}
+	for pattern in patterns {
+		native_glob_pattern(pattern, mut matches) ?
+	}
+	matches.sort()
+	return matches
+}
+
+pub const (
+	args = []string{}
+)