vim-patch:8.1.2035: recognizing octal numbers is confusing

Problem:    Recognizing octal numbers is confusing.
Solution:   Introduce scriptversion 4: do not use octal and allow for single
            quote inside numbers.
60a8de28d1

:scriptversion is N/A.

Cherry-pick Test_readfile_binary() from v8.1.0742.

Note that this patch was missing vim_str2nr() changes, and so fails the
tests; this was fixed in v8.1.2036.

src/nvim/eval.lua

@@ -344,7 +344,7 @@ return {
     stdpath={args=1},
     str2float={args=1, base=1},
     str2list={args={1, 2}, base=1},
-    str2nr={args={1, 2}},
+    str2nr={args={1, 3}},
     strcharpart={args={2, 3}},
     strchars={args={1,2}},
     strdisplaywidth={args={1, 2}},