[VPlan] Rename VPlanHCFGTransforms to VPlanTransforms (NFC).

The file is intended to gather various VPlan transformations, not only
CFG related transforms. Actually, the only transformation there is not
CFG related.

Reviewers: Ayal, gilr, hsaito, rengolin

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D70732
diff --git a/llvm/lib/Transforms/Vectorize/VPlanValue.h b/llvm/lib/Transforms/Vectorize/VPlanValue.h
index 7b6c228..464498c 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanValue.h
+++ b/llvm/lib/Transforms/Vectorize/VPlanValue.h
@@ -37,7 +37,7 @@
 // and live-outs which the VPlan will need to fix accordingly.
 class VPValue {
   friend class VPBuilder;
-  friend class VPlanHCFGTransforms;
+  friend class VPlanTransforms;
   friend class VPBasicBlock;
   friend class VPInterleavedAccessInfo;