test: replace common.fixturesDir usage

Use `common/fixtures` module instead in test-http2-client-upload.js

PR-URL: #16800
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

test/parallel/test-http2-client-upload.js

@@ -8,9 +8,9 @@ if (!common.hasCrypto)
 const assert = require('assert');
 const http2 = require('http2');
 const fs = require('fs');
-const path = require('path');
+const fixtures = require('../common/fixtures');
 
-const loc = path.join(common.fixturesDir, 'person.jpg');
+const loc = fixtures.path('person.jpg');
 let fileData;
 
 assert(fs.existsSync(loc));