I am regressing 100 repetitions with my randomly assigned treatment variable x1 as my variable of interest. How can I extract the relevant p-values from each of the 100 regressions and create a distribution of p-values as a robustness check? Does it have anything to do with bootstrapping?

Code:
forvalues i = 1(1)100{
capture drop x1
gen x1 = rbinomial(1, 0.5)
reg y x1 x2 x3 x4, r
test x1
}
Thank you!