fix: Compilation error with nested request's variable mutation receiver

Author: deve-sh

lib/runner/nested-request.js

@@ -123,8 +123,10 @@ function runNestedRequest ({ executionId, isExecutionSkipped }) {
                             // are anyway synced as the sandbox's common scope is shared across runs
                             if (result) {
                                 SYNCABLE_CONTEXT_VARIABLE_SCOPES.forEach(function (type) {
-                                    (variableMutationsFromThisExecution[type] ||= [])
-                                        .push(result[type].mutations);
+                                    variableMutationsFromThisExecution[type] = [
+                                        ...(variableMutationsFromThisExecution[type] || []),
+                                        result[type].mutations
+                                    ];
                                 });
                             }
                         },