I noticed a while ago that on Windows XP richedit controls ignored
characters typed while the mouse is captured (e.g. from holding the left
or middle button down).  Arrow keys, delete, and backspace, copying,
cutting, pasting, and everything else handled on WM_CHAR and WM_KEYDOWN
messages are also ignored.

Ignore some more registered messages.
Fix some other failures on Win2k.

user32/tests: Ignore WM_IME_SELECT message. Skip mouse hovering test if the mouse isn't where we want.