Remove set but otherwise unused variable

Recent Clang versions have enhanced -Wunused-but-set-variable which now
warns about this.

Bug: chromium:1309955
Change-Id: I9c431e8cb4f7a5dd8850d53bb5b347fa20379935
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/91930
Auto-Submit: Arthur Eubanks <aeubanks@google.com>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>

core/fxcrt/xml/cfx_xmlparser.cpp

diff --git a/core/fxcrt/xml/cfx_xmlparser.cpp b/core/fxcrt/xml/cfx_xmlparser.cpp
index 80432e0..345412a 100644
--- a/core/fxcrt/xml/cfx_xmlparser.cpp
+++ b/core/fxcrt/xml/cfx_xmlparser.cpp
@@ -105,7 +105,6 @@
   std::stack<CFX_XMLNode::Type> node_type_stack;
   WideString current_attribute_name;
   FDE_XmlSyntaxState current_parser_state = FDE_XmlSyntaxState::Text;
-  int32_t iCount = 0;
   wchar_t current_quote_character = 0;
   wchar_t current_character_to_skip_to = 0;
 
@@ -328,7 +327,6 @@
               }
 
               current_node_ = current_node_->GetParent();
-              iCount++;
             } else if (!IsXMLWhiteSpace(ch)) {
               return false;
             }