test: s/assert.equal/assert.strictEqual/

Use assert.strictEqual instead of assert.equal in tests, manually
convert types where necessary.

PR-URL: https://github.com/nodejs/node/pull/10698
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Teddy Katz <teddy.katz@gmail.com>

test/parallel/test-http-default-encoding.js

@@ -33,5 +33,5 @@ server.listen(0, function() {
 });
 
 process.on('exit', function() {
-  assert.equal(expected, result);
+  assert.strictEqual(expected, result);
 });