Remove parent-chain cycle detection from ScopeMap constructor

The cycle detection allocated a HashSet and walked the full parent chain
on every new Context (i.e. every enterScope in for loops). This was a
defensive check added long ago but is not needed in normal operation and
causes measurable overhead in hot template rendering paths.

Benchmark: +37% throughput on complexTemplateBenchmark (3,316 -> 4,542 ops/s)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: jasmith-hs

src/main/java/com/hubspot/jinjava/util/ScopeMap.java

@@ -1,16 +1,12 @@
 package com.hubspot.jinjava.util;
 
-import static com.hubspot.jinjava.util.Logging.ENGINE_LOG;
-
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
-import java.util.stream.Collectors;
 import javax.annotation.Nonnull;
 
 public class ScopeMap<K, V> implements Map<K, V> {
@@ -25,25 +21,6 @@ public ScopeMap() {
   public ScopeMap(ScopeMap<K, V> parent) {
     this.scope = new HashMap<>();
     this.parent = parent;
-
-    Set<ScopeMap<K, V>> parents = new HashSet<>();
-    if (parent != null) {
-      ScopeMap<K, V> p = parent.getParent();
-      while (p != null) {
-        parents.add(p);
-        if (parents.contains(parent)) {
-          ENGINE_LOG.error(
-            "Parent loop detected:\n{}",
-            Arrays
-              .stream(Thread.currentThread().getStackTrace())
-              .map(StackTraceElement::toString)
-              .collect(Collectors.joining("\n"))
-          );
-          break;
-        }
-        p = p.getParent();
-      }
-    }
   }
 
   public ScopeMap(ScopeMap<K, V> parent, Map<K, V> scope) {