[llvm-exegesis] deserializeMCInst(): bump SmallVector small size up to 16

[lebedev.ri]

Summary

... from 8.
VALIGNDZ128rmbik XMM0 XMM0 K1 XMM3 RDI i_0x1 i_0x0 i_0x1 instruction already has 9 components.
It does not matter much in terms of performance, but avoiding allocation seems to come with low cost here..

[lebedev.ri]

Thank you for the review!

tools/llvm-exegesis/lib/BenchmarkResult.cpp

void serializeMCInst(const llvm::MCInst &MCInst, llvm::raw_ostream &OS) {
     OS << getInstrName(MCInst.getOpcode());
     for (const auto &Op : MCInst) {
       OS << ' ';
       serializeMCOperand(Op, OS);
     }
   }
 
   void deserializeMCInst(llvm::StringRef String, llvm::MCInst &Value) {
-    llvm::SmallVector<llvm::StringRef, 8> Pieces;
+    llvm::SmallVector<llvm::StringRef, 16> Pieces;
     String.split(Pieces, " ", /* MaxSplit */ -1, /* KeepEmpty */ false);
     if (Pieces.empty()) {
       ErrorStream << "Unknown Instruction: '" << String << "'";
       return;
     }
     bool ProcessOpcode = true;
     for (llvm::StringRef Piece : Pieces) {
       if (ProcessOpcode)