[webcrypto] Refactor some layout tests.

LayoutTests/crypto/aes-key-usages-expected.txt

Index: LayoutTests/crypto/aes-key-usages-expected.txt
diff --git a/LayoutTests/accessibility/accessibility-object-detached-expected.txt b/LayoutTests/crypto/aes-key-usages-expected.txt
similarity index 39%
copy from LayoutTests/accessibility/accessibility-object-detached-expected.txt
copy to LayoutTests/crypto/aes-key-usages-expected.txt
index 183af921276bb23629132f20b8b56a87f111d947..5eba68975961709dedd110e768b27dabcf442fa5 100644
--- a/LayoutTests/accessibility/accessibility-object-detached-expected.txt
+++ b/LayoutTests/crypto/aes-key-usages-expected.txt
@@ -1,9 +1,12 @@
-This test makes sure that AccessibilityObjects are detached when the node they point to is detached.
+CONSOLE ERROR: key.usages does not permit this operation
+CONSOLE ERROR: key.usages does not permit this operation
+Make sure that the usages of an AES key are respected
 
 On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
 
 
-PASS expectedButtonRole != expectedDetachedRole is true
+PASS error is null
+PASS error is null
 PASS successfullyParsed is true
 
 TEST COMPLETE