[SVE] Replace deprecated call in changeVectorElementTypeToInteger

[bas]

Summary

Replace getVectorNumElements with getVectorElementCount;
gets rid of the warnings in several tests

[efriedma]

LGTM

[bas]

Resolve merge conflicts / generate commit message

llvm/include/llvm/CodeGen/ValueTypes.h

public:
     /// with the element type converted to an integer type with the same
     /// bitwidth.
     EVT changeVectorElementTypeToInteger() const {
       if (!isSimple())
         return changeExtendedVectorElementTypeToInteger();
       MVT EltTy = getSimpleVT().getVectorElementType();
       unsigned BitWidth = EltTy.getSizeInBits();
       MVT IntTy = MVT::getIntegerVT(BitWidth);
-      MVT VecTy = MVT::getVectorVT(IntTy, getVectorNumElements(),
-                                   isScalableVector());
+      MVT VecTy = MVT::getVectorVT(IntTy, getVectorElementCount());
       assert(VecTy.SimpleTy != MVT::INVALID_SIMPLE_VALUE_TYPE &&
              "Simple vector VT not representable by simple integer vector VT!");
       return VecTy;
     }
 
     /// Return the type converted to an equivalently sized integer or vector
     /// with integer element type. Similar to changeVectorElementTypeToInteger,
     /// but also handles scalars.