nsstring: Make ns{,C}String Sync/Send.
nsstring: Make ns{,C}String Sync/Send.

Bug: 1454021
Reviewed-by: mystor
MozReview-Commit-ID: DeBOgxxTvBR

szeged/servo,szeged/servo,emilio/servo,sadmansk/servo,SimonSapin/servo,KiChjang/servo,canaltinova/servo,saneyuki/servo,sadmansk/servo,SimonSapin/servo,cbrewster/servo,peterjoel/servo,DominoTree/servo,saneyuki/servo,avadacatavra/servo,nnethercote/servo,mbrubeck/servo,KiChjang/servo,peterjoel/servo,larsbergstrom/servo,paulrouget/servo,mbrubeck/servo,pyfisch/servo,saneyuki/servo,peterjoel/servo,sadmansk/servo,emilio/servo,cbrewster/servo,dati91/servo,ConnorGBrewster/servo,KiChjang/servo,jimberlage/servo,paulrouget/servo,emilio/servo,DominoTree/servo,ConnorGBrewster/servo,KiChjang/servo,avadacatavra/servo,canaltinova/servo,nnethercote/servo,nnethercote/servo,SimonSapin/servo,peterjoel/servo,ConnorGBrewster/servo,saneyuki/servo,notriddle/servo,dati91/servo,DominoTree/servo,dati91/servo,szeged/servo,mbrubeck/servo,peterjoel/servo,KiChjang/servo,jimberlage/servo,nnethercote/servo,emilio/servo,larsbergstrom/servo,larsbergstrom/servo,nnethercote/servo,mattnenterprise/servo,jimberlage/servo,dati91/servo,mbrubeck/servo,avadacatavra/servo,canaltinova/servo,DominoTree/servo,splav/servo,saneyuki/servo,SimonSapin/servo,KiChjang/servo,pyfisch/servo,emilio/servo,mattnenterprise/servo,avadacatavra/servo,splav/servo,nnethercote/servo,notriddle/servo,peterjoel/servo,larsbergstrom/servo,mbrubeck/servo,splav/servo,nnethercote/servo,saneyuki/servo,notriddle/servo,emilio/servo,peterjoel/servo,paulrouget/servo,DominoTree/servo,splav/servo,pyfisch/servo,DominoTree/servo,pyfisch/servo,larsbergstrom/servo,mattnenterprise/servo,sadmansk/servo,cbrewster/servo,notriddle/servo,SimonSapin/servo,splav/servo,mbrubeck/servo,sadmansk/servo,splav/servo,mattnenterprise/servo,saneyuki/servo,mbrubeck/servo,KiChjang/servo,ConnorGBrewster/servo,jimberlage/servo,mbrubeck/servo,paulrouget/servo,SimonSapin/servo,splav/servo,larsbergstrom/servo,jimberlage/servo,avadacatavra/servo,jimberlage/servo,paulrouget/servo,KiChjang/servo,saneyuki/servo,cbrewster/servo,jimberlage/servo,cbrewster/servo,saneyuki/servo,DominoTree/servo,DominoTree/servo,emilio/servo,SimonSapin/servo,saneyuki/servo,szeged/servo,ConnorGBrewster/servo,KiChjang/servo,DominoTree/servo,pyfisch/servo,dati91/servo,szeged/servo,cbrewster/servo,notriddle/servo,sadmansk/servo,larsbergstrom/servo,paulrouget/servo,peterjoel/servo,splav/servo,splav/servo,canaltinova/servo,notriddle/servo,emilio/servo,canaltinova/servo,nnethercote/servo,avadacatavra/servo,emilio/servo,ConnorGBrewster/servo,pyfisch/servo,notriddle/servo,jimberlage/servo,paulrouget/servo,peterjoel/servo,ConnorGBrewster/servo,larsbergstrom/servo,larsbergstrom/servo,mattnenterprise/servo,pyfisch/servo,szeged/servo,mattnenterprise/servo,canaltinova/servo,sadmansk/servo,mattnenterprise/servo,cbrewster/servo,nnethercote/servo,szeged/servo,szeged/servo,sadmansk/servo,jimberlage/servo,pyfisch/servo,pyfisch/servo,szeged/servo,canaltinova/servo,DominoTree/servo,notriddle/servo,peterjoel/servo,nnethercote/servo,paulrouget/servo,notriddle/servo,dati91/servo,larsbergstrom/servo,avadacatavra/servo,paulrouget/servo,ConnorGBrewster/servo,dati91/servo,canaltinova/servo,KiChjang/servo,splav/servo,dati91/servo,mattnenterprise/servo,szeged/servo,emilio/servo,pyfisch/servo,avadacatavra/servo,notriddle/servo,cbrewster/servo,SimonSapin/servo,paulrouget/servo