[clang-tools-extra] [clang-tidy][NFC] Refactor `bugprone-branch-clone` (PR #171849)

[Victor Chernyakin via cfe-commits]

================
@@ -137,19 +130,10 @@ static bool isIdenticalStmt(const ASTContext &Ctx, const Stmt *Stmt1,
       return false;
 
     // If all children of two expressions are identical, return true.
----------------
localspook wrote:

This comment seems suspicious, that's not what the code is doing, it's only returning false if not all of the children are identical, otherwise it's continuing to the big switch statement. For now I'm just leaving this as is.

https://github.com/llvm/llvm-project/pull/171849