Add x64 emitter tests

main.c

@@ -12,17 +12,9 @@
 #include "parser.c"
 #include "emit_asm_x64.c"
 
-int main(int argc, char **argv) {
-    if (argc == 2) {
-        Token_Array tokens = lex_file("expr", argv[1], strlen(argv[1]));
-        Parser parser = {tokens.data, tokens.data + tokens.len};
-        Ast *ast = parse_expr(&parser, 0);
-        FILE *file = fopen("out.s", "w");
-        emit_program(file, ast);
-        fclose(file);
-    } else {
-        vec_test();
-        lex_test();
-        parser_test();
-    }
+int main() {
+    vec_test();
+    lex_test();
+    parser_test();
+    emit_x64_test();
 }