Remove the dumb optimization.

The "optimization" was to copy 8 bytes when a flag byte of all zero bits
was read. But it was insufficiently clever and could lead to attempting
to read past the end of the input.

lzss3.py

@@ -47,11 +47,6 @@ def copybyte():
 
     while len(data) < decompressed_size:
         b = readbyte()
-        if b == 0:
-            # dumb optimization
-            for _ in range(8):
-                copybyte()
-            continue
         flags = bits(b)
         for flag in flags:
             if flag == 0:
@@ -89,11 +84,6 @@ def copybyte():
 
     while len(data) < decompressed_size:
         b = readbyte()
-        if b == 0:
-            # dumb optimization
-            for _ in range(8):
-                copybyte()
-            continue
         flags = bits(b)
         for flag in flags:
             if flag == 0: