ntdll: Remove byte reversed U+3000 (CJK space) from being checked in RtlIsTextUnicode.

[Zac Brown]

Dan Kegel wrote:
> Hang on, if you don't check U+3000 in the big endian
> case, you probably shouldn't check it in the little endian
> case, either, right?
> 
> 

Well the problem is 0x0030 maps to a regular ASCII space. In order to really 
check this particular character in byte-reversed form it will probably be 
necessary to add an independent test that ensures that both the byte-reversed 
BOM is set AND the 0x0030 character is found.

At the moment, unbreaking VS .NET 2005 seemed more important. It requires 
further investigation either way.

-Zac