tests/micropython/opt_level_lineno.py: Force test func to use bytecode.

So that the test can run the same on all targets when used with the native
emitter.

Signed-off-by: Damien George <damien@micropython.org>

tests/micropython/opt_level_lineno.py

@@ -3,4 +3,15 @@ import micropython as micropython
 # check that level 3 doesn't store line numbers
 # the expected output is that any line is printed as "line 1"
 micropython.opt_level(3)
-exec("try:\n xyz\nexcept NameError as er:\n import sys\n sys.print_exception(er)")
+
+# force bytecode emitter, because native emitter doesn't store line numbers
+exec("""
+@micropython.bytecode
+def f():
+    try:
+        xyz
+    except NameError as er:
+        import sys
+        sys.print_exception(er)
+f()
+""")

tests/micropython/opt_level_lineno.py.exp

@@ -1,3 +1,3 @@
 Traceback (most recent call last):
-  File "<string>", line 1, in <module>
+  File "<string>", line 1, in f
 NameError: name 'xyz' isn't defined

tests/run-tests.py

@@ -131,7 +131,6 @@ emitter_tests_to_skip = {
         "misc/print_exception.py",
         "micropython/emg_exc.py",
         "micropython/heapalloc_traceback.py",
-        "micropython/opt_level_lineno.py",
         "thread/thread_exc2.py",
         # These require stack-allocated slice optimisation.
         "micropython/heapalloc_slice.py",