[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-*`. But I've seen in multiple CLs in LLVM the modernize style
was recommended and code was fixed based on the style, so I added it as
well.)

The common 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
- Use inline initialization for class member variables
- Use `= default` for empty constructors / destructors
- Use `using` in place of `typedef`

Reviewers: sbc100, tlively, aardappel

Subscribers: dschuff, sunfish, jgravelle-google, yurydelendik, kripken, MatzeB, mgorny, rupprecht, llvm-commits

Differential Revision: https://reviews.llvm.org/D57500

llvm-svn: 353075
diff --git a/llvm/lib/MC/MCWasmStreamer.cpp b/llvm/lib/MC/MCWasmStreamer.cpp
index 6695a52..36571fc 100644
--- a/llvm/lib/MC/MCWasmStreamer.cpp
+++ b/llvm/lib/MC/MCWasmStreamer.cpp
@@ -34,15 +34,15 @@
 
 using namespace llvm;
 
-MCWasmStreamer::~MCWasmStreamer() {}
+MCWasmStreamer::~MCWasmStreamer() = default; // anchor.
 
 void MCWasmStreamer::mergeFragment(MCDataFragment *DF, MCDataFragment *EF) {
   flushPendingLabels(DF, DF->getContents().size());
 
-  for (unsigned i = 0, e = EF->getFixups().size(); i != e; ++i) {
-    EF->getFixups()[i].setOffset(EF->getFixups()[i].getOffset() +
+  for (unsigned I = 0, E = EF->getFixups().size(); I != E; ++I) {
+    EF->getFixups()[I].setOffset(EF->getFixups()[I].getOffset() +
                                  DF->getContents().size());
-    DF->getFixups().push_back(EF->getFixups()[i]);
+    DF->getFixups().push_back(EF->getFixups()[I]);
   }
   if (DF->getSubtargetInfo() == nullptr && EF->getSubtargetInfo())
     DF->setHasInstructions(*EF->getSubtargetInfo());
@@ -179,9 +179,9 @@
   MCDataFragment *DF = getOrCreateDataFragment();
 
   // Add the fixups and data.
-  for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
-    Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
-    DF->getFixups().push_back(Fixups[i]);
+  for (unsigned I = 0, E = Fixups.size(); I != E; ++I) {
+    Fixups[I].setOffset(Fixups[I].getOffset() + DF->getContents().size());
+    DF->getFixups().push_back(Fixups[I]);
   }
   DF->setHasInstructions(STI);
   DF->getContents().append(Code.begin(), Code.end());