Fix java_compile postprocessing.
Fix java_compile postprocessing.

It's now correct in the presence of cached artifacts.

Auditors: markcc

(sapling split of b28b65410d08843adf7019ebf7c009e703f98cae)
peiyuwang/pants,laurentgo/pants,twitter/pants,areitz/pants,lahosken/pants,peiyuwang/pants,UnrememberMe/pants,manasapte/pants,qma/pants,TansyArron/pants,digwanderlust/pants,dgomez10/xanon,twitter/pants,cevaris/pants,wisechengyi/pants,gmalmquist/pants,landism/pants,dgomez10/xanon,jsirois/pants,jtrobec/pants,twitter/pants,foursquare/pants,pantsbuild/pants,jsirois/pants,dgomez10/xanon,megaserg/pants,dturner-tw/pants,megaserg/pants,baroquebobcat/pants,jessrosenfield/pants,cevaris/pants,Gabriel439/pants,tdyas/pants,gmalmquist/pants,tdyas/pants,dturner-tw/pants,kslundberg/pants,TansyArron/pants,Gabriel439/pants,kslundberg/pants,kslundberg/pants,scode/pants,twitter/pants,kwlzn/pants,pgroudas/pants,twitter/pants,scode/pants,dgomez10/xanon,pantsbuild/pants,tejal29/pants,mateor/pants,lahosken/pants,areitz/pants,kslundberg/pants,dturner-tw/pants,gmalmquist/pants,laurentgo/pants,baroquebobcat/pants,mateor/pants,foursquare/pants,baroquebobcat/pants,di0spyr0s/pants,peiyuwang/pants,jessrosenfield/pants,UnrememberMe/pants,15Dkatz/pants,slyphon/pants,fkorotkov/pants,twitter/pants,ericzundel/pants,fkorotkov/pants,kslundberg/pants,pgroudas/pants,scode/pants,pombredanne/pants,pombredanne/pants,15Dkatz/pants,dbentley/pants,di0spyr0s/pants,lahosken/pants,di0spyr0s/pants,scode/pants,laurentgo/pants,baroquebobcat/pants,peiyuwang/pants,pombredanne/pants,qma/pants,pgroudas/pants,dturner-tw/pants,square/pants,Gabriel439/pants,tdyas/pants,dbentley/pants,UnrememberMe/pants,baroquebobcat/pants,sameerparekh/pants,foursquare/pants,foursquare/pants,peiyuwang/pants,jtrobec/pants,dbentley/pants,landism/pants,15Dkatz/pants,areitz/pants,slyphon/pants,tdyas/pants,scode/pants,mateor/pants,kwlzn/pants,square/pants,jtrobec/pants,pantsbuild/pants,jtrobec/pants,pombredanne/pants,tdyas/pants,jessrosenfield/pants,dgomez10/xanon,benjyw/pants,15Dkatz/pants,cevaris/pants,ity/pants,Gabriel439/pants,ity/pants,foursquare/pants,jtrobec/pants,ericzundel/pants,dgomez10/xanon,benjyw/pants,kwlzn/pants,sameerparekh/pants,jtrobec/pants,UnrememberMe/pants,dbentley/pants,twitter/pants,dgomez10/xanon,sid-kap/pants,qma/pants,ity/pants,dbentley/pants,sameerparekh/pants,ericzundel/pants,landism/pants,benjyw/pants,TansyArron/pants,megaserg/pants,manasapte/pants,megaserg/pants,qma/pants,manasapte/pants,qma/pants,15Dkatz/pants,lahosken/pants,sid-kap/pants,wisechengyi/pants,kslundberg/pants,dbentley/pants,UnrememberMe/pants,dturner-tw/pants,fkorotkov/pants,UnrememberMe/pants,ericzundel/pants,mateor/pants,TansyArron/pants,pantsbuild/pants,cevaris/pants,foursquare/pants,15Dkatz/pants,square/pants,scode/pants,pombredanne/pants,peiyuwang/pants,cevaris/pants,jessrosenfield/pants,peiyuwang/pants,fkorotkov/pants,fkorotkov/pants,TansyArron/pants,kwlzn/pants,dbentley/pants,tejal29/pants,twitter/pants,jessrosenfield/pants,areitz/pants,megaserg/pants,fkorotkov/pants,benjyw/pants,di0spyr0s/pants,slyphon/pants,landism/pants,tejal29/pants,sameerparekh/pants,di0spyr0s/pants,sid-kap/pants,digwanderlust/pants,pgroudas/pants,kslundberg/pants,pgroudas/pants,slyphon/pants,gmalmquist/pants,landism/pants,15Dkatz/pants,mateor/pants,TansyArron/pants,sameerparekh/pants,UnrememberMe/pants,15Dkatz/pants,landism/pants,pantsbuild/pants,dgomez10/xanon,baroquebobcat/pants,mateor/pants,foursquare/pants,tdyas/pants,dturner-tw/pants,areitz/pants,landism/pants,pgroudas/pants,fkorotkov/pants,wisechengyi/pants,pombredanne/pants,laurentgo/pants,ity/pants,kwlzn/pants,gmalmquist/pants,pantsbuild/pants,Gabriel439/pants,landism/pants,dgomez10/xanon,square/pants,fkorotkov/pants,di0spyr0s/pants,ity/pants,ity/pants,wisechengyi/pants,di0spyr0s/pants,lahosken/pants,baroquebobcat/pants,sid-kap/pants,digwanderlust/pants,wisechengyi/pants,laurentgo/pants,Gabriel439/pants,lahosken/pants,pantsbuild/pants,dgomez10/xanon,Gabriel439/pants,baroquebobcat/pants,jsirois/pants,gmalmquist/pants,slyphon/pants,areitz/pants,slyphon/pants,TansyArron/pants,sid-kap/pants,mateor/pants,scode/pants,wisechengyi/pants,kwlzn/pants,benjyw/pants,lahosken/pants,digwanderlust/pants,megaserg/pants,mateor/pants,manasapte/pants,foursquare/pants,sameerparekh/pants,tejal29/pants,cevaris/pants,jessrosenfield/pants,cevaris/pants,tdyas/pants,ericzundel/pants,foursquare/pants,ity/pants,tejal29/pants,digwanderlust/pants,manasapte/pants,sameerparekh/pants,baroquebobcat/pants,dgomez10/xanon,benjyw/pants,qma/pants,tdyas/pants,ericzundel/pants,jessrosenfield/pants,megaserg/pants,kwlzn/pants,peiyuwang/pants,manasapte/pants,lahosken/pants,sid-kap/pants,qma/pants,wisechengyi/pants,benjyw/pants,UnrememberMe/pants,gmalmquist/pants,twitter/pants,digwanderlust/pants,slyphon/pants,UnrememberMe/pants,wisechengyi/pants,ericzundel/pants,ericzundel/pants,manasapte/pants,laurentgo/pants,pombredanne/pants,areitz/pants,sid-kap/pants,jtrobec/pants,tdyas/pants,wisechengyi/pants,dturner-tw/pants