Simplify remaining "down left spine" loops

ConflictSet.cpp

@@ -1680,11 +1680,6 @@ Node *erase(Node *self, WriteContext *tls, ConflictSet::Impl *impl,
   return result;
 }
 
-struct Iterator {
-  Node *n;
-  int cmp;
-};
-
 Node *nextSibling(Node *node) {
   for (;;) {
     if (node->parent == nullptr) {
@@ -3667,12 +3662,12 @@ double internal_getMetricValue(const ConflictSet::MetricsV1 *metric) {
 
 // GCOVR_EXCL_START
 
-Iterator firstGeqLogical(Node *n, const std::span<const uint8_t> key) {
+Node *firstGeqLogical(Node *n, const std::span<const uint8_t> key) {
   auto remaining = key;
   for (;;) {
     if (remaining.size() == 0) {
       if (n->entryPresent) {
-        return {n, 0};
+        return n;
       }
       int c = getChildGeq(n, 0);
       assert(c >= 0);
@@ -3689,7 +3684,7 @@ Iterator firstGeqLogical(Node *n, const std::span<const uint8_t> key) {
       } else {
         n = nextSibling(n);
         if (n == nullptr) {
-          return {nullptr, 1};
+          return nullptr;
         }
         goto downLeftSpine;
       }
@@ -3721,14 +3716,9 @@ Iterator firstGeqLogical(Node *n, const std::span<const uint8_t> key) {
     }
   }
 downLeftSpine:
-  for (;;) {
-    if (n->entryPresent) {
-      return {n, 1};
-    }
-    int c = getChildGeq(n, 0);
-    assert(c >= 0);
-    n = getChildExists(n, c);
+  for (; !n->entryPresent; n = getFirstChildExists(n)) {
   }
+  return n;
 }
 
 void ConflictSet::check(const ReadRange *reads, Result *results,
@@ -3935,7 +3925,7 @@ void checkParentPointers(Node *node, bool &success) {
   }
 }
 
-Iterator firstGeq(Node *n, std::string_view key) {
+Node *firstGeq(Node *n, std::string_view key) {
   return firstGeqLogical(
       n, std::span<const uint8_t>((const uint8_t *)key.data(), key.size()));
 }
@@ -4006,8 +3996,8 @@ checkMaxVersion(Node *root, Node *node, InternalVersionT oldestVersion,
   auto inc = strinc(key, ok);
   if (ok) {
     auto borrowed = firstGeq(root, inc);
-    if (borrowed.n != nullptr) {
-      expected = std::max(expected, borrowed.n->entry.rangeVersion);
+    if (borrowed != nullptr) {
+      expected = std::max(expected, borrowed->entry.rangeVersion);
     }
   }
   if (maxVersion(node, impl) > oldestVersion &&