Added gdt unit and runtime tests

Updated runtime tests


Added doc comments for runtime tests


PR review


WIP


Fixed testing


Import GDT to run the unit tests


Removed redundant arch tests


Removed whitespace

test/kernel/arch/x86/rt-test.py

@@ -1,6 +1,7 @@
 def getTestCases(TestCase):
     return [
             TestCase("GDT init", [r"Init gdt", r"Done"]),
+            TestCase("GDT tests", [r"GDT: Tested loading GDT"]),
             TestCase("IDT init", [r"Init idt", r"Done"]),
             TestCase("PIT init", [r"Init pit", r".+", "Done"]),
             TestCase("Syscalls init", [r"Init syscalls", "Done"]),