[WebAssembly] clang-tidy (NFC)

Summary:
This patch fixes clang-tidy warnings on wasm-only files.
The list of checks used is:
`-*,clang-diagnostic-*,llvm-*,misc-*,-misc-unused-parameters,readability-identifier-naming,modernize-*`
(LLVM's default .clang-tidy list is the same except it does not have
`modernize-*`.)

The list of fixes are:
- Variable names start with an uppercase letter
- Function names start with a lowercase letter
- Use `auto` when you use casts so the type is evident

Reviewers: sbc100

Subscribers: dschuff, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D57499

llvm-svn: 353076
diff --git a/lld/wasm/MarkLive.cpp b/lld/wasm/MarkLive.cpp
index da70e8e..5d4b379 100644
--- a/lld/wasm/MarkLive.cpp
+++ b/lld/wasm/MarkLive.cpp
@@ -84,7 +84,7 @@
       // equal to null pointer, only reachable via direct call).
       if (Reloc.Type == R_WASM_TABLE_INDEX_SLEB ||
           Reloc.Type == R_WASM_TABLE_INDEX_I32) {
-        FunctionSymbol *FuncSym = cast<FunctionSymbol>(Sym);
+        auto *FuncSym = cast<FunctionSymbol>(Sym);
         if (FuncSym->hasTableIndex() && FuncSym->getTableIndex() == 0)
           continue;
       }