[X86] Put some cases in switch statements back on one line to be more compact and make it easier to see the similarities. NFC

It looks like someone ran clang-format over this entire file which reformatted these switches into a multiline form. But I think the single line form is more useful here.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336077 91177308-0d34-0410-b5e6-96231b3b80d8

Author: topperc