benchmark: reduce config for fs benchmarks

Remove redundant configuration values from four fs benchmark files
to reduce total benchmark suite runtime without losing code path
coverage.

Refs: nodejs/performance#186

Author: thisalihassan

benchmark/fs/read-stream-throughput.js

@@ -12,7 +12,7 @@ const filename = tmpdir.resolve(`.removeme-benchmark-garbage-${process.pid}`);
 const bench = common.createBenchmark(main, {
   encodingType: ['buf', 'asc', 'utf'],
   filesize: [1000 * 1024],
-  highWaterMark: [1024, 4096, 65535, 1024 * 1024],
+  highWaterMark: [1024, 65535, 1024 * 1024],
   n: 1024,
 });
 

benchmark/fs/readfile-promises.js

@@ -17,8 +17,6 @@ const bench = common.createBenchmark(main, {
     1024,
     512 * 1024,
     4 * 1024 ** 2,
-    8 * 1024 ** 2,
-    16 * 1024 ** 2,
     32 * 1024 ** 2,
   ],
   concurrent: [1, 10],

benchmark/fs/write-stream-throughput.js

@@ -11,7 +11,7 @@ const filename = tmpdir.resolve(`.removeme-benchmark-garbage-${process.pid}`);
 const bench = common.createBenchmark(main, {
   dur: [5],
   encodingType: ['buf', 'asc', 'utf'],
-  size: [2, 1024, 65535, 1024 * 1024],
+  size: [1024, 65535, 1024 * 1024],
 });
 
 function main({ dur, encodingType, size }) {

benchmark/fs/writefile-promises.js

@@ -13,7 +13,7 @@ let filesWritten = 0;
 const bench = common.createBenchmark(main, {
   duration: [5],
   encodingType: ['buf', 'asc', 'utf'],
-  size: [2, 1024, 65535, 1024 * 1024],
+  size: [1024, 65535, 1024 * 1024],
   concurrent: [1, 10],
 });