Write a function that returns true if it's possible to build a phrase s1 using only the characters from another phrase s2.
canBuild("got 2 go", "gogogo 2 today") ➞ true
canBuild("sit on top", "its a moo point") ➞ true
canBuild("long high add or", "highway road go long") ➞ false
canBuild("fill tuck mid", "truck falls dim") ➞ false