Take 2 on "Fix ajax to always expect an Error object, per #10646."

We can't use jQuery.error to rethrow anymore since it constructs a new Error from its supposedly-string arg. Also, older IE stringifies Error objects into "[object Error]" so I've loosened the unit test criteria.

This reverts commit 586fb059.

src/ajax.js

@@ -752,10 +752,10 @@ jQuery.extend({
 			} catch (e) {
 				// Propagate exception as error if not done
 				if ( state < 2 ) {
-					done( -1, e.message );
+					done( -1, e );
 				// Simply rethrow otherwise
 				} else {
-					jQuery.error( e.message );
+					throw e;
 				}
 			}
 		}

test/unit/ajax.js

@@ -1616,7 +1616,7 @@ test("jQuery.ajax() - malformed JSON", function() {
 		},
 		error: function(xhr, msg, detailedMsg) {
 			equal( "parsererror", msg, "A parse error occurred." );
-			ok( /^(Invalid|SyntaxError|exception)/i.test(detailedMsg), "Detailed parsererror message provided" );
+			ok( /(invalid|error|exception)/i.test(detailedMsg), "Detailed parsererror message provided" );
 	  		start();
 		}
 	});