[webcrypto] Fix the key usages used by some layout tests.

LayoutTests/crypto/clone-rsaHashedKey-private.html

Index: LayoutTests/crypto/clone-rsaHashedKey-private.html
diff --git a/LayoutTests/crypto/clone-rsaHashedKey-private.html b/LayoutTests/crypto/clone-rsaHashedKey-private.html
index be3526a872921bf06795d43e31de030b929479af..8c05815a700a927be3c0a8b551ec02a74727487a 100644
--- a/LayoutTests/crypto/clone-rsaHashedKey-private.html
+++ b/LayoutTests/crypto/clone-rsaHashedKey-private.html
@@ -14,14 +14,14 @@ description("Tests structured cloning of RSA private keys (with a hash)");
 
 jsTestIsAsync = true;
 
-// Tests the 48 permutations of keys generated by:
+// Tests the 12 permutations of keys generated by:
 //   kPossibleAlgorithms x kPossibleExtractable x kPossibleKeyUsages x kPossibleKeyData x kPossibleHashAlgorithms
 //
 // For practical reasons these tests are not exhaustive.
 
 var kPossibleAlgorithms = ['RSASSA-PKCS1-v1_5'];
 var kPossibleExtractable = [true, false];
-var kPossibleKeyUsages = [[], ['sign'], ['verify'], ['sign', 'verify']];
+var kPossibleKeyUsages = [[], ['sign']];
 var kPossibleHashAlgorithms = ['SHA-1', 'SHA-256', 'SHA-512'];
 
 var kPossibleKeyData = [