Use foreach loop over constant operands. NFC.

A number of places had explicit loops over Constant::operands().
Just use foreach loops where possible.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240694 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Bitcode/Writer/ValueEnumerator.cpp

@@ -691,9 +691,7 @@ void ValueEnumerator::EnumerateOperandType(const Value *V) {
 
   // This constant may have operands, make sure to enumerate the types in
   // them.
-  for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i) {
-    const Value *Op = C->getOperand(i);
-
+  for (const Value *Op : C->operands()) {
     // Don't enumerate basic blocks here, this happens as operands to
     // blockaddress.
     if (isa<BasicBlock>(Op))