I don't want anyone getting the idea that the `-X` flag they might have
used has anything to do with why the `+` is working for them

Always run tests with encoding=utf-8, regardless of user locale
Don't set &encoding after startup in tests

Helped-By: Michael Reed <m.reed@mykolab.com>

This is equivalent to patches 7.4.396, 7.4.445 and 7.4.598.

vim-patch:7.4.396

Problem:    When 'clipboard' is "unnamed", :g/pat/d is very slow.
(Praful)
Solution:   Only set the clipboard after the last delete. (Christian
Brabandt)

https://github.com/vim/vim/commit/1f285eb49a709e00552f7bef7e74efff5ae79026

vim-patch:7.4.445

Problem:    Clipboard may be cleared on startup.
Solution:   Set clip_did_set_selection to -1 during startup. (Christian
	    Brabandt)

https://github.com/vim/vim/commit/1a19d37d90f037c09183ba68fdddf70ab8ee179a

vim-patch:7.4.598

Problem:    ":tabdo windo echo 'hi'" causes "* register not to be
changed.
	    (Salman Halim)
Solution:   Change how clip_did_set_selection is used and add
	    clipboard_needs_update and global_change_count.  (Christian
	    Brabandt)

https://github.com/vim/vim/commit/af6a579263a688f30bfbbee72b28d08cc7e0f3d4

Co-Author: @bfredl

Re: https://github.com/neovim/neovim/issues/2676

patch 7.4.813
Problem: It is not possible to save and restore character search state.
Solution: Add getcharsearch() and setcharsearch().  (James McCoy)

https://github.com/vim/vim/releases/tag/v7.4.813
https://github.com/vim/vim/releases/tag/v7.4.826

Signed-off-by: James McCoy <vega.james@gmail.com>

The python-client has it's own test suite, and this isn't even run: see
the has('nvim') call.

Taken from
https://github.com/bfredl/neovim/commit/1acf4ace5224cf12472d2b086f55a74714491d6f
with minor modifications.

"Now that you've done the necessary cleanup, why not go ahead and merge
this." @bfredl

The test is also split in several blocks and heavily modernized.  This was
done to prevent the following quoting and escaping problems during migration:
- the vim command `put =...` treats double quotes as the start of a comment so
  they have to be escaped with a backslash
- when inserting control characters on the command line they have to be
  escaped with <C-V>

The parts one and two of the test are functional identical so they are wrapped
in a local function. The only difference was which letters where used to test
the same feature.

Part six did test a flag in 'cpoptions' that has been removed in neovim.  It
has therefore been removed as well.

Reviewed-by: Michael Reed <Pyrohh@users.noreply.github.com>