tests: Add a test for native code on pyboard.

tests/pybnative/while.py

@@ -0,0 +1,14 @@
+@micropython.native
+def f(led, n):
+    led.off()
+    i = 0
+    while i < n:
+        led.toggle()
+        d = pyb.delay
+        d(50) # pyb.delay(50) doesn't work!
+        i += 1
+        print(i)
+    led.off()
+
+f(pyb.LED(1), 2)
+f(pyb.LED(2), 4)

tests/pybnative/while.py.exp

@@ -0,0 +1,6 @@
+1
+2
+1
+2
+3
+4

tests/run-tests

@@ -115,7 +115,7 @@ def main():
             test_dirs = ('basics', 'float', 'import', 'io', 'misc')
         else:
             # run pyboard tests
-            test_dirs = ('basics', 'float', 'pyb', 'inlineasm')
+            test_dirs = ('basics', 'float', 'pyb', 'pybnative', 'inlineasm')
         tests = sorted(test_file for test_files in (glob('{}/*.py'.format(dir)) for dir in test_dirs) for test_file in test_files)
     else:
         # tests explicitly given