test: fix unreliable known_issues test

test/known_issues/known_issues.status

@@ -0,0 +1,20 @@
+prefix known_issues
+
+# If a known issue does not apply to a platform, list the test name in the
+# appropriate section below, without ".js", followed by ": SKIP". Example:
+# sample-test                        : SKIP
+
+[true] # This section applies to all platforms
+
+[$system==win32]
+test-stdout-buffer-flush-on-exit: SKIP
+
+[$system==linux]
+
+[$system==macos]
+
+[$system==solaris]
+
+[$system==freebsd]
+
+[$system==aix]

test/known_issues/test-stdout-buffer-flush-on-exit.js

@@ -5,16 +5,23 @@ require('../common');
 const assert = require('assert');
 const execSync = require('child_process').execSync;
 
-const longLine = 'foo bar baz quux quuz aaa bbb ccc'.repeat(65536);
+const lineSeed = 'foo bar baz quux quuz aaa bbb ccc';
 
 if (process.argv[2] === 'child') {
+  const longLine = lineSeed.repeat(parseInt(process.argv[4], 10));
   process.on('exit', () => {
     console.log(longLine);
   });
   process.exit();
 }
 
-const cmd = `${process.execPath} ${__filename} child`;
-const stdout = execSync(cmd).toString().trim();
+[16, 18, 20].forEach((exponent) => {
+  const bigNum = Math.pow(2, exponent);
+  const longLine = lineSeed.repeat(bigNum);
+  const cmd = `${process.execPath} ${__filename} child ${exponent} ${bigNum}`;
+  const stdout = execSync(cmd).toString().trim();
+
+  assert.strictEqual(stdout, longLine, `failed with exponent ${exponent}`);
+});
+
 
-assert.strictEqual(stdout, longLine);