test: fix test for buffer regression #649

- pass a regexp to assert.throws()

Author: joyeecheung

test/parallel/test-buffer-regression-649.js

@@ -6,8 +6,14 @@ const SlowBuffer = require('buffer').SlowBuffer;
 
 // Regression test for https://github.com/nodejs/node/issues/649.
 const len = 1422561062959;
-assert.throws(() => Buffer(len).toString('utf8'));
-assert.throws(() => SlowBuffer(len).toString('utf8'));
-assert.throws(() => Buffer.alloc(len).toString('utf8'));
-assert.throws(() => Buffer.allocUnsafe(len).toString('utf8'));
-assert.throws(() => Buffer.allocUnsafeSlow(len).toString('utf8'));
+const lenLimitMsg = /^RangeError: Invalid typed array length$/;
+assert.throws(() => Buffer(len).toString('utf8'),
+              lenLimitMsg);
+assert.throws(() => SlowBuffer(len).toString('utf8'),
+              lenLimitMsg);
+assert.throws(() => Buffer.alloc(len).toString('utf8'),
+              lenLimitMsg);
+assert.throws(() => Buffer.allocUnsafe(len).toString('utf8'),
+              lenLimitMsg);
+assert.throws(() => Buffer.allocUnsafeSlow(len).toString('utf8'),
+              lenLimitMsg);