[NFC][InstCombine] PR38708 - inefficient pattern for high-bits checking 3.

The last, non-canonical variant:
https://godbolt.org/z/aCMsPk
https://rise4fun.com/Alive/I6f

It can only happen due to the extra use on the inner shift.
But here it is ok.

https://bugs.llvm.org/show_bug.cgi?id=38708

llvm-svn: 342184