Move testing knowledge from community to microsoft layer

Relocates the six P1+P2 testing-domain articles (18 files: .md + .good.al + .bad.al each) from community/knowledge/testing/ to microsoft/knowledge/testing/ per maintainer request. Pure git-mv rename; no content or frontmatter changes.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

microsoft/knowledge/testing/asserterror-needs-expectederror-and-code.bad.al

@@ -0,0 +1,18 @@
+codeunit 50409 "Test AssertError Bad"
+{
+    Subtype = Test;
+
+    [Test]
+    procedure BlankNameIsRejectedWithSpecificError()
+    var
+        Customer: Record Customer;
+    begin
+        Customer.Init();
+        Customer.Name := '';
+
+        // Bare asserterror: passes if ANY error is raised. A relation error,
+        // a permission error, or a typo elsewhere would all satisfy it — so
+        // this never proves the blank-name guard is the thing that fired.
+        asserterror Customer.TestField(Name);
+    end;
+}