Use a local viminfo file when running the old tests.

This is required after defaulting to `nocp`, so that ~/.nviminfo
files don't interfere with the old legacy tests.
Remove superfluous settings from legacy tests.
Reimplement :drop (vim-patch:0)

The :drop ex command was inadvertently removed when removing FEAT_GUI.
This patch reintroduces it.
vim-patch:7.4.434

Problem:    gettabvar() is not consistent with getwinvar() and getbufvar().
Solution:   Return a dict with all variables when the varname is empty.
	    (Yasuhiro Matsumoto)

https://code.google.com/p/vim/source/detail?r=v7-4-434
vim-patch:7.4.442

Problem:    Using unitinialized variable.
Solution:   Pass the first window of the tabpage.

https://code.google.com/p/vim/source/detail?r=v7-4-442
Merge pull request #1699 from three-comrades/fix-viminfo

Use a local viminfo file when running the old tests.
Merge pull request #1638 from Grimy/ex-drop

Reimplement :drop
Merge pull request #1704 from fwalch/vim-7.4.434

vim-patch:7.4.434, vim-patch:7.4.442