Do a single check to see if the blob has been seen already.

Instead of checking if it has been seen for every instance before
check_emulator_for_lib is called, call check_emulator_for_lib and check if it
has been seen once inside of check_emulator_for_lib.
Bump up ALL_LIBS_SIZE to 16KB.

Also warn if we come within 100 characters of the max size.