test: replace [].join() with ''.repeat()

Replace [].join calls with the more modern .repeat PR-URL: #12305 Reviewed-By: Benjamin Gruenbaum <[email protected]> Reviewed-By: Gibson Fahnestock <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Luigi Pinca <[email protected]> Reviewed-By: Daijiro Wachi <[email protected]> Reviewed-By: Alexey Orlenko <[email protected]> Reviewed-By: Vse Mozhet Byt <[email protected]> Reviewed-By: Yuta Hiroto <[email protected]>

Author: JacksonTian

test/parallel/test-child-process-send-utf8.js

@@ -3,7 +3,7 @@ const common = require('../common');
 constassert=require('assert');
 constfork=require('child_process').fork;
 
-constexpected=Array(1e5).join('ßßßß');
+constexpected='ßßßß'.repeat(1e5-1);
 if(process.argv[2]==='child'){
 process.send(expected);
 }else{

test/parallel/test-stringbytes-external.js

@@ -23,9 +23,9 @@ assert.strictEqual(b[1], 0);
 assert.strictEqual(ucs2_control,c);
 
 // now create big strings
-constsize=1+(1<<20);
-write_str=Array(size).join(write_str);
-ucs2_control=Array(size).join(ucs2_control);
+constsize=1<<20;
+write_str=write_str.repeat(size);
+ucs2_control=ucs2_control.repeat(size);
 
 // check resultant buffer and output string
 b=Buffer.from(write_str,'ucs2');
@@ -110,7 +110,7 @@ const PRE_3OF4_APEX = Math.ceil((EXTERN_APEX / 4) * 3) - RADIOS;
 
 // https://github.com/nodejs/node/issues/1024
 {
-consta=Array(1<<20).join('x');
+consta='x'.repeat(1<<20-1);
 constb=Buffer.from(a,'ucs2').toString('ucs2');
 constc=Buffer.from(b,'utf8').toString('utf8');