[WebCrypto] Test updates to not use keyUsage empty

LayoutTests/crypto/clone-ecKey-private.html

Index: LayoutTests/crypto/clone-ecKey-private.html
diff --git a/LayoutTests/crypto/clone-ecKey-private.html b/LayoutTests/crypto/clone-ecKey-private.html
index bee675e5249f2901a4f7d98d23f8caa419de5082..d796c1a9e5e2e72c6f6b915cd61416ddebacb860 100644
--- a/LayoutTests/crypto/clone-ecKey-private.html
+++ b/LayoutTests/crypto/clone-ecKey-private.html
@@ -21,14 +21,14 @@ function signOrDeriveBits(algorithmName) {
     return ['deriveBits'];
 }
 
-// Tests the 24 permutations of keys generated by:
+// Tests the 12 permutations of keys generated by:
 //   kPossibleAlgorithms x kPossibleExtractable x kPossibleKeyUsages x kPossibleCurves
 //
 // For practical reasons these tests are not exhaustive.
 
 var kPossibleAlgorithms = ['ECDSA', 'ECDH'];
 var kPossibleExtractable = [true, false];
-var kPossibleKeyUsages = [[], signOrDeriveBits];
+var kPossibleKeyUsages = [signOrDeriveBits];
 var kPossibleNamedCurves = ['P-256', 'P-384', 'P-521'];
 
 // A mapping from curve name, to PKCS8 data (hex-encoded) for a valid private key.