[JS] Use heap allocation when initializing quickjs sandbox (#13286)

- In case of large string the sandbox initialization failed because of an OOM
    * so allocate a new string in the heap
    * and free it after use.
  - it requires a quickjs update since we need to export some symbols (stringToNewUTF8 and free).

Author: calixteman

external/quickjs/quickjs-eval.js

@@ -71,20 +71,26 @@ class Sandbox {
     }
 
     let success = false;
+    let buf = 0;
     try {
       const sandboxData = JSON.stringify(data);
       // "pdfjsScripting.initSandbox..." MUST be the last line to be evaluated
       // since the returned value is used for the communication.
       code.push(`pdfjsScripting.initSandbox({ data: ${sandboxData} })`);
+      buf = this._module.stringToNewUTF8(code.join("\n"));
 
       success = !!this._module.ccall(
         "init",
         "number",
-        ["string", "number"],
-        [code.join("\n"), this._alertOnError]
+        ["number", "number"],
+        [buf, this._alertOnError]
       );
     } catch (error) {
       console.error(error);
+    } finally {
+      if (buf) {
+        this._module.ccall("free", "number", ["number"], [buf]);
+      }
     }
 
     if (success) {