[SE-0311] Add Sendable requirement to TaskLocal.
[SE-0311] Add Sendable requirement to TaskLocal.

This is part of SE-0311 that was not implemented.
Fixes rdar://77441933.

glessard/swift,atrick/swift,JGiola/swift,atrick/swift,benlangmuir/swift,gregomni/swift,hooman/swift,ahoppen/swift,gregomni/swift,benlangmuir/swift,apple/swift,hooman/swift,gregomni/swift,glessard/swift,roambotics/swift,gregomni/swift,apple/swift,xwu/swift,xwu/swift,apple/swift,gregomni/swift,rudkx/swift,glessard/swift,ahoppen/swift,gregomni/swift,roambotics/swift,hooman/swift,hooman/swift,glessard/swift,benlangmuir/swift,benlangmuir/swift,xwu/swift,ahoppen/swift,apple/swift,hooman/swift,xwu/swift,roambotics/swift,JGiola/swift,atrick/swift,roambotics/swift,apple/swift,JGiola/swift,ahoppen/swift,benlangmuir/swift,xwu/swift,glessard/swift,xwu/swift,ahoppen/swift,JGiola/swift,atrick/swift,benlangmuir/swift,JGiola/swift,rudkx/swift,apple/swift,roambotics/swift,rudkx/swift,atrick/swift,atrick/swift,rudkx/swift,xwu/swift,ahoppen/swift,JGiola/swift,hooman/swift,rudkx/swift,roambotics/swift,rudkx/swift,glessard/swift,hooman/swift