Add method to remove interpreter errors

Author: Matt Coley

src/main/java/com/hubspot/jinjava/interpret/JinjavaInterpreter.java

@@ -650,6 +650,10 @@ public void addError(TemplateError templateError) {
     }
   }
 
+  public void removeError(int index) {
+    errors.remove(index);
+  }
+
   public int getScopeDepth() {
     return scopeDepth;
   }