[stdlib] Fix return type of swift_{uint64,int64,float*}ToString (#24181)
[stdlib] Fix return type of swift_{uint64,int64,float*}ToString (#24181)

The return type of these functions are uint64_t in Stubs.cpp but UInt in the Swift code; this changes the Swift code to match the C++ return type.

Found when compiling the stdlib for WebAssembly, which requires that all return types match: UInt maps to i32 while uint64_t maps to i64, so functions calling these functions fail the validation.
gregomni/swift,allevato/swift,lorentey/swift,jmgc/swift,JGiola/swift,roambotics/swift,allevato/swift,jckarter/swift,benlangmuir/swift,lorentey/swift,jckarter/swift,jckarter/swift,allevato/swift,gregomni/swift,gregomni/swift,stephentyrone/swift,jmgc/swift,JGiola/swift,JGiola/swift,hooman/swift,atrick/swift,tkremenek/swift,atrick/swift,hooman/swift,hooman/swift,hooman/swift,karwa/swift,parkera/swift,airspeedswift/swift,CodaFi/swift,apple/swift,gribozavr/swift,roambotics/swift,parkera/swift,jmgc/swift,CodaFi/swift,harlanhaskins/swift,apple/swift,harlanhaskins/swift,karwa/swift,CodaFi/swift,roambotics/swift,CodaFi/swift,gribozavr/swift,airspeedswift/swift,airspeedswift/swift,glessard/swift,ahoppen/swift,gribozavr/swift,rudkx/swift,xwu/swift,xwu/swift,gregomni/swift,allevato/swift,lorentey/swift,xwu/swift,gregomni/swift,rudkx/swift,parkera/swift,harlanhaskins/swift,apple/swift,jckarter/swift,rudkx/swift,lorentey/swift,xwu/swift,nathawes/swift,airspeedswift/swift,aschwaighofer/swift,jmgc/swift,airspeedswift/swift,benlangmuir/swift,apple/swift,nathawes/swift,harlanhaskins/swift,parkera/swift,ahoppen/swift,karwa/swift,allevato/swift,ahoppen/swift,aschwaighofer/swift,harlanhaskins/swift,JGiola/swift,jckarter/swift,airspeedswift/swift,lorentey/swift,rudkx/swift,harlanhaskins/swift,parkera/swift,nathawes/swift,karwa/swift,ahoppen/swift,jckarter/swift,atrick/swift,atrick/swift,CodaFi/swift,gregomni/swift,lorentey/swift,xwu/swift,aschwaighofer/swift,aschwaighofer/swift,airspeedswift/swift,benlangmuir/swift,stephentyrone/swift,benlangmuir/swift,CodaFi/swift,tkremenek/swift,karwa/swift,nathawes/swift,tkremenek/swift,aschwaighofer/swift,tkremenek/swift,stephentyrone/swift,nathawes/swift,gribozavr/swift,apple/swift,roambotics/swift,nathawes/swift,glessard/swift,jmgc/swift,benlangmuir/swift,karwa/swift,xwu/swift,atrick/swift,stephentyrone/swift,apple/swift,glessard/swift,gribozavr/swift,gribozavr/swift,aschwaighofer/swift,JGiola/swift,parkera/swift,lorentey/swift,roambotics/swift,karwa/swift,glessard/swift,jmgc/swift,hooman/swift,tkremenek/swift,gribozavr/swift,rudkx/swift,lorentey/swift,parkera/swift,glessard/swift,karwa/swift,stephentyrone/swift,hooman/swift,rudkx/swift,nathawes/swift,stephentyrone/swift,aschwaighofer/swift,glessard/swift,JGiola/swift,tkremenek/swift,allevato/swift,gribozavr/swift,jmgc/swift,ahoppen/swift,xwu/swift,parkera/swift,hooman/swift,tkremenek/swift,atrick/swift,stephentyrone/swift,allevato/swift,benlangmuir/swift,CodaFi/swift,roambotics/swift,jckarter/swift,ahoppen/swift,harlanhaskins/swift