Adds method call support for all functions in the patch, but it cannot
be fully ported due to missing tests for:
- getcwd(): requires chdir() and Test_chdir_func() from v8.1.1291.
Note that the method call tests for getreg() and getregtype() were
removed in v8.2.1547, which has already been ported, but doesn't seem to
have been replaced with a new test...
This patch also makes getchangelist()'s argument optional (defaults to
the current buffer).
eval.txt includes a typo for gettabwinvar(), which is fixed in
v8.1.1952.