[gardening] Cleanup SILDefaultWitnessTable before I change it.

Just to make review easier.

Author: gottesmm

lib/SIL/Verifier/SILVerifier.cpp

@@ -7687,26 +7687,26 @@ void SILWitnessTable::verify(const SILModule &M) const {
 }
 
 /// Verify that a default witness table follows invariants.
-void SILDefaultWitnessTable::verify(const SILModule &M) const {
+void SILDefaultWitnessTable::verify(const SILModule &mod) const {
 #ifndef NDEBUG
-  for (const Entry &E : getEntries()) {
+  for (const Entry &entry : getEntries()) {
     // FIXME: associated type witnesses.
-    if (!E.isValid() || E.getKind() != SILWitnessTable::Method)
+    if (!entry.isValid() || entry.getKind() != SILWitnessTable::Method)
       continue;
 
-    SILFunction *F = E.getMethodWitness().Witness;
-    if (!F)
+    auto *witnessFunction = entry.getMethodWitness().Witness;
+    if (!witnessFunction)
       continue;
 
 #if 0
     // FIXME: For now, all default witnesses are private.
-    assert(F->hasValidLinkageForFragileRef(IsSerialized) &&
+    assert(witnessFunction->hasValidLinkageForFragileRef(IsSerialized) &&
            "Default witness tables should not reference "
            "less visible functions.");
 #endif
 
-    assert(F->getLoweredFunctionType()->getRepresentation() ==
-           SILFunctionTypeRepresentation::WitnessMethod &&
+    assert(witnessFunction->getLoweredFunctionType()->getRepresentation() ==
+               SILFunctionTypeRepresentation::WitnessMethod &&
            "Default witnesses must have witness_method representation.");
   }
 #endif