benchmark: remove buffer benchmarks redundancy

PR-URL: #45735
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Daeyeon Jeong <daeyeon.dev@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>

benchmark/buffers/buffer-copy.js

@@ -5,6 +5,12 @@ const bench = common.createBenchmark(main, {
   bytes: [0, 8, 128, 32 * 1024],
   partial: ['true', 'false'],
   n: [6e6]
+}, {
+  combinationFilter: (p) => {
+    return (p.partial === 'false' && p.bytes === 0) ||
+           (p.partial !== 'false' && p.bytes !== 0);
+  },
+  test: { partial: 'false', bytes: 0 },
 });
 
 function main({ n, bytes, partial }) {

benchmark/buffers/buffer-indexof.js

@@ -19,9 +19,14 @@ const searchStrings = [
 
 const bench = common.createBenchmark(main, {
   search: searchStrings,
-  encoding: ['utf8', 'ucs2'],
+  encoding: ['undefined', 'utf8', 'ucs2'],
   type: ['buffer', 'string'],
   n: [5e4]
+}, {
+  combinationFilter: (p) => {
+    return (p.type === 'buffer' && p.encoding === 'undefined') ||
+           (p.type !== 'buffer' && p.encoding !== 'undefined');
+  },
 });
 
 function main({ n, search, encoding, type }) {

benchmark/buffers/buffer-tostring.js

@@ -3,10 +3,15 @@
 const common = require('../common.js');
 
 const bench = common.createBenchmark(main, {
-  encoding: ['utf8', 'ascii', 'latin1', 'hex', 'UCS-2'],
+  encoding: ['', 'utf8', 'ascii', 'latin1', 'hex', 'UCS-2'],
   args: [0, 1, 3],
   len: [1, 64, 1024],
   n: [1e6]
+}, {
+  combinationFilter: (p) => {
+    return (p.args === 0 && p.encoding === '') ||
+           (p.args !== 0 && p.encoding !== '');
+  },
 });
 
 function main({ encoding, args, len, n }) {