[LV] Remove duplicate name set of vector header basic block. NFC

[michaelmaitland]

Summary

The preheader was named explicitly in 256c6b0ba14e8a7ab6373b61b7193ea8c0a3651c
which makes setting the name in prior commit 95b2aa511eea1f31e183a2a3aed4d2aa852d089c
unnecessary.

[michaelmaitland]

ping

[fhahn]

LGTM, thanks!

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

for (Instruction &I : BB->instructionsWithoutDebug()) {
                                     : "");
       }
     }
 
     VPBlockUtils::insertBlockAfter(new VPBasicBlock(), VPBB);
     VPBB = cast<VPBasicBlock>(VPBB->getSingleSuccessor());
   }
 
-  HeaderVPBB->setName("vector.body");
-
   // After here, VPBB should not be used.
   VPBB = nullptr;
 
   addUsersInExitBlock(HeaderVPBB, MiddleVPBB, OrigLoop, *Plan);
 
   assert(isa<VPRegionBlock>(Plan->getVectorLoopRegion()) &&
          !Plan->getVectorLoopRegion()->getEntryBasicBlock()->empty() &&
          "entry block must be set to a VPRegionBlock having a non-empty entry "