tests/run-tests.py: Skip list sort stress test for ESP8266.

This commit marks the "stress/list_sort.py" test to be skipped when
running on ESP8266.

The test just takes too long without yielding to the OS whilst doing the
sort, causing the internal software watchdog to kick in and reboot the
board.

Signed-off-by: Alessandro Gatti <a.gatti@frob.it>

tests/run-tests.py

@@ -180,6 +180,9 @@ emitter_tests_to_skip = {
 # Tests to skip on specific targets.
 # These are tests that are difficult to detect that they should not be run on the given target.
 platform_tests_to_skip = {
+    "esp8266": (
+        "stress/list_sort.py",  # watchdog kicks in because it takes too long
+    ),
     "minimal": (
         "basics/class_inplace_op.py",  # all special methods not supported
         "basics/subclass_native_init.py",  # native subclassing corner cases not support