[ast] Avoid useless empty check

Change-Id: I7c12b78dc06e13becc45c3df7c23929d1fa6a86c
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/20000
Reviewed-by: dan sinclair <dsinclair@google.com>
diff --git a/src/ast/identifier_expression.cc b/src/ast/identifier_expression.cc
index 7adb6bc..d14d5f4 100644
--- a/src/ast/identifier_expression.cc
+++ b/src/ast/identifier_expression.cc
@@ -36,7 +36,7 @@
 IdentifierExpression::~IdentifierExpression() = default;
 
 std::string IdentifierExpression::path() const {
-  if (segments_.empty() || segments_.size() < 2) {
+  if (segments_.size() < 2) {
     return "";
   }