tests: drop experiments

tests/test_experiments.py

-import pytest
-
-
-def test_terminal(board, board_shell):
-    board.serial_miniterm()
-
-
-@pytest.mark.board("mox")
-def test_skip(board_uboot):
-    assert board_uboot.run("help")
-    assert board_uboot.run("boot")
-
-
-#def test_access(