Fix incorrect calculation with gcs path for backup corpus. (#4863)
Fix incorrect calculation with gcs path for backup corpus. (#4863)

Fixes https://github.com/google/oss-fuzz/issues/4857
google/oss-fuzz,google/oss-fuzz,skia-dev/oss-fuzz,googlefonts/oss-fuzz,google/oss-fuzz,googlefonts/oss-fuzz,robertswiecki/oss-fuzz,skia-dev/oss-fuzz,googlefonts/oss-fuzz,skia-dev/oss-fuzz,googlefonts/oss-fuzz,robertswiecki/oss-fuzz,google/oss-fuzz,robertswiecki/oss-fuzz,google/oss-fuzz,skia-dev/oss-fuzz,skia-dev/oss-fuzz,skia-dev/oss-fuzz,googlefonts/oss-fuzz,googlefonts/oss-fuzz,skia-dev/oss-fuzz,google/oss-fuzz,google/oss-fuzz,skia-dev/oss-fuzz,google/oss-fuzz,skia-dev/oss-fuzz,google/oss-fuzz,robertswiecki/oss-fuzz,robertswiecki/oss-fuzz,robertswiecki/oss-fuzz,skia-dev/oss-fuzz,googlefonts/oss-fuzz,robertswiecki/oss-fuzz,googlefonts/oss-fuzz,robertswiecki/oss-fuzz,robertswiecki/oss-fuzz,googlefonts/oss-fuzz,skia-dev/oss-fuzz,robertswiecki/oss-fuzz,googlefonts/oss-fuzz,google/oss-fuzz,google/oss-fuzz,robertswiecki/oss-fuzz