bench: add benchmark/benchmark.factory.js to random/base/randn

Adds the conventional `:factory`, `:factory:seed=<integer>`, and
`:factory:seed=<array>` benchmarks for `@stdlib/random/base/randn.factory`.

Author: claude

lib/node_modules/@stdlib/random/base/randn/benchmark/benchmark.factory.js

@@ -0,0 +1,106 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var bench = require( '@stdlib/bench' );
+var Uint32Array = require( '@stdlib/array/uint32' );
+var isnan = require( '@stdlib/math/base/assert/is-nan' );
+var minstd = require( '@stdlib/random/base/minstd-shuffle' );
+var format = require( '@stdlib/string/format' );
+var pkg = require( './../package.json' ).name;
+var factory = require( './../lib' ).factory;
+
+
+// MAIN //
+
+bench( format( '%s:factory', pkg ), function benchmark( b ) {
+	var f;
+	var i;
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		f = factory();
+		if ( typeof f !== 'function' ) {
+			b.fail( 'should return a function' );
+		}
+	}
+	b.toc();
+	if ( isnan( f() ) ) {
+		b.fail( 'should not return NaN' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});
+
+bench( format( '%s:factory:seed=<integer>', pkg ), function benchmark( b ) {
+	var opts;
+	var f;
+	var i;
+
+	opts = {
+		'seed': 1
+	};
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		opts.seed += i;
+		f = factory( opts );
+		if ( typeof f !== 'function' ) {
+			b.fail( 'should return a function' );
+		}
+	}
+	b.toc();
+	if ( isnan( f() ) ) {
+		b.fail( 'should not return NaN' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});
+
+bench( format( '%s:factory:seed=<array>', pkg ), function benchmark( b ) {
+	var seed;
+	var opts;
+	var f;
+	var i;
+
+	opts = {};
+
+	seed = new Uint32Array( 10 );
+	for ( i = 0; i < seed.length; i++ ) {
+		seed[ i ] = minstd();
+	}
+	opts.seed = seed;
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		opts.seed[ 0 ] = i + 1;
+		f = factory( opts );
+		if ( typeof f !== 'function' ) {
+			b.fail( 'should return a function' );
+		}
+	}
+	b.toc();
+	if ( isnan( f() ) ) {
+		b.fail( 'should not return NaN' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});