[llvm] Refactoring llvm-ir2vec.cpp for better separation of concerns in the Tooling classes (PR #170078)

[S. VenkataKeerthy via llvm-commits]

================
@@ -151,7 +152,30 @@ static cl::opt<EmbeddingLevel>
           cl::init(FunctionLevel), cl::sub(EmbeddingsSubCmd),
           cl::cat(CommonCategory));
 
+struct Triplet {
----------------
svkeerthy wrote:

Add doc here and below?

Also, initialize all members to 0?

https://github.com/llvm/llvm-project/pull/170078