Improve LayoutTest output for Errors

LayoutTests/crypto/hmac-generateKey-parseAlgorithm-failures.html

Index: LayoutTests/crypto/hmac-generateKey-parseAlgorithm-failures.html
diff --git a/LayoutTests/crypto/hmac-generateKey-parseAlgorithm-failures.html b/LayoutTests/crypto/hmac-generateKey-parseAlgorithm-failures.html
index c61b478981fbd46135138d72f976dd05cc0313c4..5aad6102a6b83eb4541c442f26656c5b1156bff6 100644
--- a/LayoutTests/crypto/hmac-generateKey-parseAlgorithm-failures.html
+++ b/LayoutTests/crypto/hmac-generateKey-parseAlgorithm-failures.html
@@ -16,34 +16,42 @@ extractable = true;
 keyUsages = ['sign', 'verify'];
 
 Promise.resolve(null).then(function() {
+    debug("\ngenerateKey() with a length of -3...");
     return crypto.subtle.generateKey({name: 'hmac', hash: {name: 'sha-256'}, length: -3}, extractable , keyUsages);
 }).then(failAndFinishJSTest, function(result) {
     logError(result);
 
+    debug("\ngenerateKey() with hash name empty string...");
     return crypto.subtle.generateKey({name: 'hmac', hash: {name: ''}, length: 48}, extractable , keyUsages);
 }).then(failAndFinishJSTest, function(result) {
     logError(result);
 
+    debug("\ngenerateKey() with a length of 5000000000 ...");
     return crypto.subtle.generateKey({name: 'hmac', hash: {name: 'sha-256'}, length: 5000000000}, extractable , keyUsages);
 }).then(failAndFinishJSTest, function(result) {
     logError(result);
 
+    debug("\ngenerateKey() with length NaN...");
     return crypto.subtle.generateKey({name: 'hmac', hash: {name: 'sha-256'}, length: NaN}, extractable , keyUsages);
 }).then(failAndFinishJSTest, function(result) {
     logError(result);
 
+    debug("\ngenerateKey() with length that is Infinity...");
     return crypto.subtle.generateKey({name: 'hmac', hash: {name: 'sha-256'}, length: Infinity}, extractable , keyUsages);
 }).then(failAndFinishJSTest, function(result) {
     logError(result);
 
+    debug("\ngenerateKey() with length that is minus Infinity...");
     return crypto.subtle.generateKey({name: 'hmac', hash: {name: 'sha-256'}, length: -Infinity}, extractable , keyUsages);
 }).then(failAndFinishJSTest, function(result) {
     logError(result);
 
+    debug("\ngenerateKey() with length that is a string...");
     return crypto.subtle.generateKey({name: 'hmac', hash: {name: 'sha-256'}, length: crypto}, extractable , keyUsages);
 }).then(failAndFinishJSTest, function(result) {
     logError(result);
 
+    debug("\ngenerateKey() with length that is a undefined...");
     return crypto.subtle.generateKey({name: 'hmac', hash: {name: 'sha-256'}, length: undefined}, extractable , keyUsages);
 }).then(failAndFinishJSTest, function(result) {
     logError(result);