test: remove unnecessary test flags

This commit removes unnecessary flags used when starting
tests via the "// Flags:" directive.

PR-URL: https://github.com/nodejs/node/pull/25277
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

test/parallel/test-buffer-of-no-deprecation.js

@@ -1,4 +1,3 @@
-// Flags: --pending-deprecation --no-warnings
 'use strict';
 
 const common = require('../common');

test/parallel/test-util-inspect.js

@@ -19,8 +19,6 @@
 // DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
-
-// Flags: --expose-internals
 'use strict';
 const common = require('../common');
 const assert = require('assert');

test/parallel/test-v8-deserialize-buffer.js

@@ -1,4 +1,3 @@
-// Flags: --pending-deprecation --no-warnings
 'use strict';
 
 const common = require('../common');

test/parallel/test-v8-serdes.js

@@ -1,4 +1,4 @@
-// Flags: --expose-gc --expose-internals
+// Flags: --expose-internals
 
 'use strict';