test: use strictEqual in cwd-enoent

Changed all references from assert.Equal() to assert.strictEqual().
PR-URL: #10077
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

Author: jdharmon

test/parallel/test-cwd-enoent.js

@@ -21,6 +21,6 @@ proc.stdout.pipe(process.stdout);
 proc.stderr.pipe(process.stderr);
 
 proc.once('exit',common.mustCall(function(exitCode,signalCode){
-assert.equal(exitCode,0);
-assert.equal(signalCode,null);
+assert.strictEqual(exitCode,0);
+assert.strictEqual(signalCode,null);
 }));