[Refactor](Prepared Statement) remove implementation in legacy planner

fe/fe-core/src/main/cup/sql_parser.cup

@@ -766,8 +766,6 @@ nonterminal BackupStmt backup_stmt;
 nonterminal AbstractBackupTableRefClause opt_backup_table_ref_list;
 nonterminal Boolean backup_exclude_or_not;
 nonterminal RestoreStmt restore_stmt;
-nonterminal PrepareStmt prepare_stmt;
-nonterminal ExecuteStmt execute_stmt;
 
 nonterminal SelectList select_clause, select_list, select_sublist;
 
@@ -5869,22 +5867,6 @@ expr_or_default ::=
     :}
     ;
 
-prepare_stmt ::=
-    KW_PREPARE variable_name:name KW_FROM select_stmt:s
-    {:
-        RESULT = new PrepareStmt(s, name);
-        s.setPlaceHolders(parser.placeholder_expr_list);
-        parser.placeholder_expr_list.clear();
-    :}
-    ;
-
-execute_stmt ::=
-    KW_EXECUTE variable_name:name args_list:s
-    {:
-        RESULT = new ExecuteStmt(name, s);
-    :}
-    ;
-
 literal_values ::=
     literal:value
     {:

fe/fe-core/src/main/java/org/apache/doris/analysis/Analyzer.java

@@ -508,9 +508,6 @@ public GlobalState(Env env, ConnectContext context) {
 
     private final GlobalState globalState;
 
-    // Attached PrepareStmt
-    public PrepareStmt prepareStmt;
-
     private final InferPredicateState inferPredicateState;
 
     // An analyzer stores analysis state for a single select block. A select block can be
@@ -618,14 +615,6 @@ public int getCallDepth() {
         return callDepth;
     }
 
-    public void setPrepareStmt(PrepareStmt stmt) {
-        prepareStmt = stmt;
-    }
-
-    public PrepareStmt getPrepareStmt() {
-        return prepareStmt;
-    }
-
     public void setInlineView(boolean inlineView) {
         isInlineView = inlineView;
     }