Ensure all builds are optimized, fix #421
Ensure all builds are optimized, fix #421

-O1 gives better coverage for fuzzing.
ssbr/oss-fuzz,FeliciaLim/oss-fuzz,ssbr/oss-fuzz,googlefonts/oss-fuzz,kcc/oss-fuzz,google/oss-fuzz,google/oss-fuzz,kcc/oss-fuzz,vitalybuka/oss-fuzz,oliverchang/oss-fuzz,google/oss-fuzz,robertswiecki/oss-fuzz,FeliciaLim/oss-fuzz,robertswiecki/oss-fuzz,googlefonts/oss-fuzz,google/oss-fuzz,skia-dev/oss-fuzz,google/oss-fuzz,google/oss-fuzz,robertswiecki/oss-fuzz,robertswiecki/oss-fuzz,robertswiecki/oss-fuzz,skia-dev/oss-fuzz,googlefonts/oss-fuzz,googlefonts/oss-fuzz,googlefonts/oss-fuzz,robertswiecki/oss-fuzz,oliverchang/oss-fuzz,skia-dev/oss-fuzz,robertswiecki/oss-fuzz,google/oss-fuzz,google/oss-fuzz,vitalybuka/oss-fuzz,kcc/oss-fuzz,ssbr/oss-fuzz,kcc/oss-fuzz,google/oss-fuzz,skia-dev/oss-fuzz,google/oss-fuzz,kcc/oss-fuzz,FeliciaLim/oss-fuzz,skia-dev/oss-fuzz,vitalybuka/oss-fuzz,oliverchang/oss-fuzz,vitalybuka/oss-fuzz,FeliciaLim/oss-fuzz,skia-dev/oss-fuzz,google/oss-fuzz,skia-dev/oss-fuzz,skia-dev/oss-fuzz,googlefonts/oss-fuzz,ssbr/oss-fuzz,skia-dev/oss-fuzz,googlefonts/oss-fuzz,googlefonts/oss-fuzz,oliverchang/oss-fuzz,vitalybuka/oss-fuzz,ssbr/oss-fuzz,FeliciaLim/oss-fuzz,robertswiecki/oss-fuzz,robertswiecki/oss-fuzz,robertswiecki/oss-fuzz,googlefonts/oss-fuzz,skia-dev/oss-fuzz,robertswiecki/oss-fuzz,skia-dev/oss-fuzz,googlefonts/oss-fuzz,oliverchang/oss-fuzz