Improve microbench.js

- ensure handler behavior does not depend on n argument
- load and save reference file in node.js
- add -s filename option to name the output reference file
- add targets in Makefile for tests and bencharks using node.js
- fix incorrect timings when not using high resolution timer
- use performance timer in node.js
- output performance factor instead of percentage
- use smaller threshold by default
- add benchmarks for:
    date_parse(), prop_update(), prop_clone(), array_slice()
    global_func_call(),

Makefile

@@ -525,10 +525,25 @@ testall-32: all test-32 microbench-32 test2o-32 test2-32
 
 testall-complete: testall testall-32
 
+node-test:
+	node tests/test_closure.js
+	node tests/test_language.js
+	node tests/test_builtin.js
+	node tests/test_loop.js
+	node tests/test_bignum.js
+
+node-microbench:
+	node tests/microbench.js -s microbench-node.txt
+	node --jitless tests/microbench.js -s microbench-node-jitless.txt
+
 bench-v8: qjs
 	make -C tests/bench-v8
 	./qjs -d tests/bench-v8/combined.js
 
+node-bench-v8:
+	make -C tests/bench-v8
+	node --jitless tests/bench-v8/combined.js
+
 tests/bjson.so: $(OBJDIR)/tests/bjson.pic.o
 	$(CC) $(LDFLAGS) -shared -o $@ $^ $(LIBS)