Employer is withdrawing application after getting NOIR from USCIS. Another Employer filing for transfer

You will be deemed by USCIS to have been out of status as of that date. Should the new employer's petition be approved though, you can apply for the H1B visa at the US consulate overseas and return right back to the US with a new H1B visa stamp in your passport. Make sure the new employer requests "consular notification "to protect against the eventuality USCIS will deem you out of status as of the day of the withdrawal or denial.

You should talk to the new employer's immigration attorney about this immediately. S/he should know about this circumstance, but may not, unless s/he is told by you. I always recommend the employee-beneficiary of an employer-sponsored visa petition should communicate with the attorney working in his/her matter. Just because the employer-petitioner is paying the attorney's fees, does not mean that the employer's attorney does not also represent the employee-beneficiary. In this circumstance, you may know very critical information that the employer does not, and which the employer has not communicated to its attorney. Time may be of the essence in getting the new employer's petition submitted to USCIS.

You appear to be concerned about your lawful stay in the United States and wish to remain in the country legally. If that is in fact correct, delegate any of your issues to the counsel of record, as legally appropriate in this situation.