[js] performance : bad language detection triggers 3 times

[GuillaumeDua]

Reproduce the issue :

• use the live demo
• switch language to js

Current behavior :

23:17:54.817 [object ace.details.code.policies.language.highlighters.use_hljs].highlight: 
	poor language relevance [4/10] for language [Javascript] 
	Perhaps the code is too small ? (70 characters): 
Object { language: "Javascript", value: 'auto i = <span class="hljs-number">42</span>; <span class="hljs-comment">// test</span>\n<span class="hljs-attr">std</span>::cout &lt;&lt; <span class="hljs-string">&quot;- result:&quot;</span> &lt;&lt; i &lt;&lt; <span class="hljs-string">&#x27;\\n&#x27;</span>;\n<span class="hljs-keyword">return</span> i;\n', relevance: 4, illegal: false, _emitter: {…}, _top: {…}, code: `auto i = 42; // test\nstd::cout << "- result:" << i << '\\n';\nreturn i;\n` }
awesome-code-element.js:1835:33

3 times

Expected behavior :

Same ouput, once