import-in-the-middle failing on Node.js main branch

Ref: https://ci.nodejs.org/view/Node.js-citgm/job/citgm-smoker/3295/

 added 115 packages in 9s
 > import-in-the-middle@1.4.2 test
 > c8 --check-coverage --lines 85 imhotap --runner 'node test/runtest' --files test/{hook,low-level,other,get-esm-exports}/*
 TAP version 13
 1..25
 ok 1 test/get-esm-exports/v20-get-esm-exports.js
   ---
   stdout: >-
     export let name1, name2/*,  */; // also var
        contains exports: name1,name2
     export const name1 = 1, name2 = 2/*,  */; // also var, let
        contains exports: name1,name2
     export function functionName() { /*  */ }
        contains exports: functionName
     export class ClassName { /*  */ }
        contains exports: ClassName
     export function* generatorFunctionName() { /*  */ }
        contains exports: generatorFunctionName
     export const { name1, name2: bar } = o;
        contains exports: name1,bar
     export const [ name1, name2 ] = array;
        contains exports: name1,name2
     let name1, nameN; export { name1, /* , */ nameN };
        contains exports: name1,nameN
     let variable1, variable2, nameN; export { variable1 as name1, variable2 as
     name2, /* , */ nameN };
        contains exports: name1,name2,nameN
     let variable1; export { variable1 as "string name" };
        contains exports: string name
     let name1; export { name1 as default /*,  */ };
        contains exports: default
     export default expression;
        contains exports: default
     export default function functionName() { /*  */ }
        contains exports: default
     export default class ClassName { /*  */ }
        contains exports: default
     export default function* generatorFunctionName() { /*  */ }
        contains exports: default
     export default function () { /*  */ }
        contains exports: default
     export default class { /*  */ }
        contains exports: default
     export default function* () { /*  */ }
        contains exports: default
     export * from "module-name";
        contains exports: *
     export * as name1 from "module-name";
        contains exports: name1
     export { name1, /* , */ nameN } from "module-name";
        contains exports: name1,nameN
     export { import1 as name1, import2 as name2, /* , */ nameN } from
     "module-name";
        contains exports: name1,name2,nameN
     export { default, /* , */ } from "module-name";
        contains exports: default
     export { default as name1 } from "module-name";
        contains exports: name1
   stderr: ''
   ...
 ok 2 test/hook/define-property.js
 ok 3 test/hook/dynamic-import-default.js
 ok 4 test/hook/dynamic-import-default.mjs
 ok 5 test/hook/dynamic-import.js
 ok 6 test/hook/dynamic-import.mjs
 ok 7 test/hook/loader.mjs
 ok 8 test/hook/remove.mjs
 ok 9 test/hook/static-import-default.mjs
 ok 10 test/hook/static-import-disabled.mjs
 ok 11 test/hook/static-import-package-internals-enabled.mjs
 ok 12 test/hook/static-import-package-internals.mjs
 ok 13 test/hook/static-import-package.mjs
 ok 14 test/hook/static-import.mjs
 ok 15 test/hook/v18-static-import-assert.mjs
 ok 16 test/low-level/dynamic-import-default.js
 ok 17 test/low-level/dynamic-import-default.mjs
 ok 18 test/low-level/dynamic-import.js
 ok 19 test/low-level/remove.mjs
 ok 20 test/low-level/sanitized-url.mjs
 ok 21 test/low-level/static-import-default.mjs
 ok 22 test/low-level/static-import-disabled.mjs
 ok 23 test/low-level/static-import.mjs
 ok 24 test/other/executable
 not ok 25 test/other/import-executable.mjs
   ---
   stdout: ''
   stderr: |-
     node:internal/process/promises:262
               triggerUncaughtException(err, true /* fromPromise */);
               ^
     AssertionError [ERR_ASSERTION]: Missing expected rejection (TypeError).
         at async file:///home/iojs/tmp/citgm_tmp/8aff2e39-3a70-4ba0-832b-b7bb6f1d8719/import-in-the-middle/test/other/import-executable.mjs:7:3 {
       generatedMessage: false,
       code: 'ERR_ASSERTION',
       actual: undefined,
       expected: { name: 'TypeError', code: 'ERR_UNKNOWN_FILE_EXTENSION' },
       operator: 'rejects'
     }
     Node.js v21.0.0-pre
   ...

@bengl @Qard Not sure if this is an expected breaking change in the main branch or a CITGM problem or what, but since it is failing on all platforms, I figure I better get attention on it sooner rather than later.

Start with the CITGM job linked in the issue and the failing test/other/import-executable.mjs case. Reproduce the failure on Node.js main, then compare the expected ERR_UNKNOWN_FILE_EXTENSION rejection with the observed behavior and determine whether the test or the underlying Node.js behavior needs attention; done means the cause is resolved and the CITGM run passes.