No, they would never do that, especially with Imran Khan being in power. Pakistan has actually got into some troubles with the US (Trump) since last year which led to the US sanctioning Pakistan. Iran and Pakistan have recently been developing quite a deep relationship indeed.
Around 4 years ago when the topic of the airstrike on Iranian nuclear sites was very hot, Turkey, a NATO member, announced they will not allow their soil as a base for any sort of attack on Iran. They said the same about the Iraq invasion, actually.
Unfortunately, the only country that would allow this to happen is Saudi Arabia and other smaller Persian Gulf states, but mainly Saudi Arabia.
Pakistan will remain more and less neutral but let’s be sure, many Shia from Pakistan will be willing to fight but in an off-the-record manner.
The Source for the first Screenshot: U.S. Relations with Pakistan Hit Rock Bottom With Trump’s Tweets