test: use default assertion messages

The string literal messages in addons-napi/test_buffer/test.js are less
helpful than the default messages, so use the default messages.

Backport-PR-URL: #19447
PR-URL: #16808
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

test/addons-napi/test_buffer/test.js

@@ -5,20 +5,17 @@ const common = require('../../common');
 const binding = require(`./build/${common.buildType}/test_buffer`);
 const assert = require('assert');
 
-assert.strictEqual(binding.newBuffer().toString(), binding.theText,
-                   'buffer returned by newBuffer() has wrong contents');
-assert.strictEqual(binding.newExternalBuffer().toString(), binding.theText,
-                   'buffer returned by newExternalBuffer() has wrong contents');
+assert.strictEqual(binding.newBuffer().toString(), binding.theText);
+assert.strictEqual(binding.newExternalBuffer().toString(), binding.theText);
 console.log('gc1');
 global.gc();
 assert.strictEqual(binding.getDeleterCallCount(), 1, 'deleter was not called');
-assert.strictEqual(binding.copyBuffer().toString(), binding.theText,
-                   'buffer returned by copyBuffer() has wrong contents');
+assert.strictEqual(binding.copyBuffer().toString(), binding.theText);
 
 let buffer = binding.staticBuffer();
 assert.strictEqual(binding.bufferHasInstance(buffer), true,
                    'buffer type checking fails');
-assert.strictEqual(binding.bufferInfo(buffer), true, 'buffer data is accurate');
+assert.strictEqual(binding.bufferInfo(buffer), true);
 buffer = null;
 global.gc();
 console.log('gc2');