Auto merge of #19326 - servo:jdm-patch-2, r=asajeffrey
Auto merge of #19326 - servo:jdm-patch-2, r=asajeffrey

Use same build environment during mutation testing.

ccache complains that the C++ compiler doesn't match the cached version.

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ConnorGBrewster/servo,DominoTree/servo,canaltinova/servo,saneyuki/servo,anthgur/servo,cbrewster/servo,nnethercote/servo,dati91/servo,splav/servo,peterjoel/servo,fiji-flo/servo,jimberlage/servo,KiChjang/servo,nnethercote/servo,saneyuki/servo,nnethercote/servo,saneyuki/servo,upsuper/servo,szeged/servo,jimberlage/servo,SimonSapin/servo,DominoTree/servo,dsandeephegde/servo,rnestler/servo,jimberlage/servo,upsuper/servo,fiji-flo/servo,avadacatavra/servo,mattnenterprise/servo,szeged/servo,pyfisch/servo,KiChjang/servo,splav/servo,pyfisch/servo,ConnorGBrewster/servo,saneyuki/servo,thiagopnts/servo,pyfisch/servo,cbrewster/servo,mbrubeck/servo,SimonSapin/servo,DominoTree/servo,larsbergstrom/servo,dati91/servo,upsuper/servo,cbrewster/servo,SimonSapin/servo,fiji-flo/servo,DominoTree/servo,mbrubeck/servo,SimonSapin/servo,KiChjang/servo,canaltinova/servo,dsandeephegde/servo,sadmansk/servo,notriddle/servo,DominoTree/servo,DominoTree/servo,KiChjang/servo,larsbergstrom/servo,emilio/servo,pyfisch/servo,paulrouget/servo,rnestler/servo,notriddle/servo,dsandeephegde/servo,pyfisch/servo,SimonSapin/servo,paulrouget/servo,canaltinova/servo,CJ8664/servo,notriddle/servo,nnethercote/servo,mbrubeck/servo,mbrubeck/servo,peterjoel/servo,splav/servo,ConnorGBrewster/servo,peterjoel/servo,szeged/servo,upsuper/servo,larsbergstrom/servo,szeged/servo,mattnenterprise/servo,notriddle/servo,cbrewster/servo,avadacatavra/servo,fiji-flo/servo,fiji-flo/servo,emilio/servo,thiagopnts/servo,notriddle/servo,notriddle/servo,pyfisch/servo,paulrouget/servo,splav/servo,rnestler/servo,rnestler/servo,paulrouget/servo,DominoTree/servo,mattnenterprise/servo,larsbergstrom/servo,dsandeephegde/servo,sadmansk/servo,CJ8664/servo,paulrouget/servo,peterjoel/servo,ConnorGBrewster/servo,jimberlage/servo,szeged/servo,thiagopnts/servo,splav/servo,canaltinova/servo,dati91/servo,upsuper/servo,emilio/servo,notriddle/servo,fiji-flo/servo,jimberlage/servo,upsuper/servo,anthgur/servo,larsbergstrom/servo,jimberlage/servo,fiji-flo/servo,mattnenterprise/servo,paulrouget/servo,SimonSapin/servo,peterjoel/servo,szeged/servo,avadacatavra/servo,anthgur/servo,avadacatavra/servo,ConnorGBrewster/servo,dsandeephegde/servo,avadacatavra/servo,thiagopnts/servo,thiagopnts/servo,ConnorGBrewster/servo,KiChjang/servo,paulrouget/servo,avadacatavra/servo,mbrubeck/servo,canaltinova/servo,emilio/servo,mbrubeck/servo,dsandeephegde/servo,avadacatavra/servo,emilio/servo,peterjoel/servo,jimberlage/servo,nnethercote/servo,peterjoel/servo,emilio/servo,saneyuki/servo,dati91/servo,pyfisch/servo,notriddle/servo,nnethercote/servo,splav/servo,sadmansk/servo,larsbergstrom/servo,pyfisch/servo,cbrewster/servo,mattnenterprise/servo,nnethercote/servo,nnethercote/servo,thiagopnts/servo,dati91/servo,sadmansk/servo,thiagopnts/servo,sadmansk/servo,anthgur/servo,DominoTree/servo,emilio/servo,notriddle/servo,mbrubeck/servo,splav/servo,CJ8664/servo,peterjoel/servo,szeged/servo,szeged/servo,dati91/servo,CJ8664/servo,saneyuki/servo,dsandeephegde/servo,dsandeephegde/servo,KiChjang/servo,saneyuki/servo,saneyuki/servo,rnestler/servo,anthgur/servo,KiChjang/servo,splav/servo,rnestler/servo,szeged/servo,sadmansk/servo,mattnenterprise/servo,KiChjang/servo,saneyuki/servo,DominoTree/servo,rnestler/servo,larsbergstrom/servo,SimonSapin/servo,emilio/servo,peterjoel/servo,CJ8664/servo,paulrouget/servo,CJ8664/servo,larsbergstrom/servo,paulrouget/servo,cbrewster/servo,szeged/servo,mbrubeck/servo,mattnenterprise/servo,emilio/servo,emilio/servo,jimberlage/servo,KiChjang/servo,upsuper/servo,ConnorGBrewster/servo,larsbergstrom/servo,pyfisch/servo,rnestler/servo,pyfisch/servo,saneyuki/servo,anthgur/servo,sadmansk/servo,paulrouget/servo,anthgur/servo,SimonSapin/servo,cbrewster/servo,dati91/servo,canaltinova/servo,canaltinova/servo,DominoTree/servo,mattnenterprise/servo,splav/servo,upsuper/servo,splav/servo,CJ8664/servo,sadmansk/servo,CJ8664/servo,larsbergstrom/servo,cbrewster/servo,nnethercote/servo,thiagopnts/servo,peterjoel/servo,canaltinova/servo,jimberlage/servo,dati91/servo,notriddle/servo,ConnorGBrewster/servo,KiChjang/servo,nnethercote/servo,anthgur/servo,fiji-flo/servo,avadacatavra/servo