[docs] Remove `-lFuzzingEngine` reference from base-builder image readme.
[docs] Remove `-lFuzzingEngine` reference from base-builder image readme.

//cc @jonathanmetzman
googlefonts/oss-fuzz,robertswiecki/oss-fuzz,robertswiecki/oss-fuzz,skia-dev/oss-fuzz,skia-dev/oss-fuzz,googlefonts/oss-fuzz,google/oss-fuzz,google/oss-fuzz,FeliciaLim/oss-fuzz,google/oss-fuzz,googlefonts/oss-fuzz,FeliciaLim/oss-fuzz,googlefonts/oss-fuzz,skia-dev/oss-fuzz,google/oss-fuzz,robertswiecki/oss-fuzz,skia-dev/oss-fuzz,robertswiecki/oss-fuzz,google/oss-fuzz,skia-dev/oss-fuzz,google/oss-fuzz,googlefonts/oss-fuzz,skia-dev/oss-fuzz,robertswiecki/oss-fuzz,robertswiecki/oss-fuzz,FeliciaLim/oss-fuzz,googlefonts/oss-fuzz,robertswiecki/oss-fuzz,googlefonts/oss-fuzz,googlefonts/oss-fuzz,googlefonts/oss-fuzz,google/oss-fuzz,robertswiecki/oss-fuzz,google/oss-fuzz,robertswiecki/oss-fuzz,skia-dev/oss-fuzz,skia-dev/oss-fuzz,google/oss-fuzz,skia-dev/oss-fuzz,google/oss-fuzz,googlefonts/oss-fuzz,skia-dev/oss-fuzz,skia-dev/oss-fuzz,robertswiecki/oss-fuzz,FeliciaLim/oss-fuzz,google/oss-fuzz,FeliciaLim/oss-fuzz,robertswiecki/oss-fuzz