[X86] Rename tests for bypassing slow division (NFC)

For tests on bypassing slow division there's no need to be
Atom-specific. The patch renames all tests on division bypassing
and makes their names more consistent:

  atom-bypass-slow-division.ll -> bypass-slow-division-32.ll
  (tests verifying correctness of divl-to-divb bypassing)

  atom-bypass-slow-division-64.ll -> bypass-slow-division-64.ll
  (tests verifying correctness of divq-to-divl bypassing)

  slow-div.ll -> bypass-slow-division-tune.ll
  (tests verifying that bypassing is enabled only when appropriate)

Differential Revision: https://reviews.llvm.org/D28197

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291802 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/test/CodeGen/X86/atom-bypass-slow-division.ll b/test/CodeGen/X86/bypass-slow-division-32.ll
similarity index 100%
rename from test/CodeGen/X86/atom-bypass-slow-division.ll
rename to test/CodeGen/X86/bypass-slow-division-32.ll

diff --git a/test/CodeGen/X86/atom-bypass-slow-division-64.ll b/test/CodeGen/X86/bypass-slow-division-64.ll
similarity index 100%
rename from test/CodeGen/X86/atom-bypass-slow-division-64.ll
rename to test/CodeGen/X86/bypass-slow-division-64.ll

diff --git a/test/CodeGen/X86/slow-div.ll b/test/CodeGen/X86/bypass-slow-division-tune.ll
similarity index 100%
rename from test/CodeGen/X86/slow-div.ll
rename to test/CodeGen/X86/bypass-slow-division-tune.ll