[lldb][NFC] Allow range-based for-loops on VariableList

Summary:
Adds support for doing range-based for-loops on LLDB's VariableList and
modernises all the index-based for-loops in LLDB where possible.

Reviewers: labath, jdoerfert

Reviewed By: labath

Subscribers: JDevlieghere, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D70668
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp
index 88534d0..4966ac1 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp
@@ -648,9 +648,7 @@
 
   if (vars.GetSize()) {
     if (type) {
-      for (size_t i = 0; i < vars.GetSize(); ++i) {
-        VariableSP var_sp = vars.GetVariableAtIndex(i);
-
+      for (VariableSP var_sp : vars) {
         if (ClangASTContext::AreTypesSame(
                 *type, var_sp->GetType()->GetFullCompilerType()))
           return var_sp;