Rewrite exp(n*ln(x)) as a power : exp2pow

exp2pow rewrites expression of the form exp(n*ln(x)) as a power of x.
Input :

exp2pow(exp(n*ln(x)))

Output :

x^n

Note the difference with lncollect :
lncollect(exp(n*ln(x))) = exp(n*log(x))
lncollect(exp(2*ln(x))) = exp(2*log(x))
exp2pow(exp(2*ln(x))) = x^2
But :
lncollect(exp(ln(x)+ln(x))) = x^2
exp2pow(exp(ln(x)+ln(x))) = x^(1+1)