test: remove literals that obscure assert messages

Remove string literals as messages to `assert.strictEqual()`. They can
be misleading here (where perhaps the reason an assertino failed isn't
that the deleter wasn't called but rather was called too many times.

Backport-PR-URL: #19265
PR-URL: #17642
Reviewed-By: Anna Henningsen <[email protected]>
Reviewed-By: Ruben Bridgewater <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: Jon Moss <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Anatoli Papirovski <[email protected]>
Reviewed-By: Michael Dawson <[email protected]>

Author: Trott

test/addons-napi/test_buffer/test.js

@@ -9,14 +9,13 @@ 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.getDeleterCallCount(), 1);
 assert.strictEqual(binding.copyBuffer().toString(), binding.theText);
 
 let buffer = binding.staticBuffer();
-assert.strictEqual(binding.bufferHasInstance(buffer), true,
-                   'buffer type checking fails');
+assert.strictEqual(binding.bufferHasInstance(buffer), true);
 assert.strictEqual(binding.bufferInfo(buffer), true);
 buffer = null;
 global.gc();
 console.log('gc2');
-assert.strictEqual(binding.getDeleterCallCount(), 2, 'deleter was not called');
+assert.strictEqual(binding.getDeleterCallCount(), 2);