Do not convert NODE_STR to NODE_LIT when the string is hash key

parse.y converted NODE_STR when the string is hash key like

```
h1 = {"str1" => 1}
m1("str2" => 2)
m2({"str3" => 3})
```

This commit stop the conversion.
`static_literal_node_p` needs to know the node is for hash key or not
for the optimization.

compile.c

@@ -4706,7 +4706,7 @@ compile_args(rb_iseq_t *iseq, LINK_ANCHOR *const ret, const NODE *node, NODE **k
 }
 
 static inline int
-static_literal_node_p(const NODE *node, const rb_iseq_t *iseq)
+static_literal_node_p(const NODE *node, const rb_iseq_t *iseq, bool hash_key)
 {
     switch (nd_type(node)) {
       case NODE_LIT:
@@ -4721,7 +4721,7 @@ static_literal_node_p(const NODE *node, const rb_iseq_t *iseq)
         return TRUE;
       case NODE_STR:
       case NODE_FILE:
-        return ISEQ_COMPILE_DATA(iseq)->option->frozen_string_literal;
+        return hash_key || ISEQ_COMPILE_DATA(iseq)->option->frozen_string_literal;
       default:
         return FALSE;
     }
@@ -4841,10 +4841,10 @@ compile_array(rb_iseq_t *iseq, LINK_ANCHOR *const ret, const NODE *node, int pop
         int count = 1;
 
         /* pre-allocation check (this branch can be omittable) */
-        if (static_literal_node_p(RNODE_LIST(node)->nd_head, iseq)) {
+        if (static_literal_node_p(RNODE_LIST(node)->nd_head, iseq, false)) {
             /* count the elements that are optimizable */
             const NODE *node_tmp = RNODE_LIST(node)->nd_next;
-            for (; node_tmp && static_literal_node_p(RNODE_LIST(node_tmp)->nd_head, iseq); node_tmp = RNODE_LIST(node_tmp)->nd_next)
+            for (; node_tmp && static_literal_node_p(RNODE_LIST(node_tmp)->nd_head, iseq, false); node_tmp = RNODE_LIST(node_tmp)->nd_next)
                 count++;
 
             if ((first_chunk && stack_len == 0 && !node_tmp) || count >= min_tmp_ary_len) {
@@ -4899,7 +4899,7 @@ compile_array(rb_iseq_t *iseq, LINK_ANCHOR *const ret, const NODE *node, int pop
 static int
 compile_array_1(rb_iseq_t *iseq, LINK_ANCHOR *const ret, const NODE *node)
 {
-    if (static_literal_node_p(node, iseq)) {
+    if (static_literal_node_p(node, iseq, false)) {
         VALUE ary = rb_ary_hidden_new(1);
         rb_ary_push(ary, static_literal_value(node, iseq));
         OBJ_FREEZE(ary);
@@ -4917,7 +4917,7 @@ compile_array_1(rb_iseq_t *iseq, LINK_ANCHOR *const ret, const NODE *node)
 static inline int
 static_literal_node_pair_p(const NODE *node, const rb_iseq_t *iseq)
 {
-    return RNODE_LIST(node)->nd_head && static_literal_node_p(RNODE_LIST(node)->nd_head, iseq) && static_literal_node_p(RNODE_LIST(RNODE_LIST(node)->nd_next)->nd_head, iseq);
+    return RNODE_LIST(node)->nd_head && static_literal_node_p(RNODE_LIST(node)->nd_head, iseq, true) && static_literal_node_p(RNODE_LIST(RNODE_LIST(node)->nd_next)->nd_head, iseq, true);
 }
 
 static int

parse.y

@@ -6877,10 +6877,6 @@ assocs		: assoc
 assoc		: arg_value tASSOC arg_value
                     {
                     /*%%%*/
-                        if (nd_type_p($1, NODE_STR)) {
-                            nd_set_type($1, NODE_LIT);
-                            RB_OBJ_WRITE(p->ast, &RNODE_LIT($1)->nd_lit, rb_fstring(RNODE_LIT($1)->nd_lit));
-                        }
                         $$ = list_append(p, NEW_LIST($1, &@$), $3);
                     /*% %*/
                     /*% ripper: assoc_new!($1, $3) %*/
@@ -14941,6 +14937,7 @@ nd_type_st_key_enable_p(NODE *node)
       case NODE_FLOAT:
       case NODE_RATIONAL:
       case NODE_IMAGINARY:
+      case NODE_STR:
       case NODE_LINE:
       case NODE_FILE:
         return true;
@@ -14955,6 +14952,8 @@ nd_st_key(struct parser_params *p, NODE *node)
     switch (nd_type(node)) {
       case NODE_LIT:
         return RNODE_LIT(node)->nd_lit;
+      case NODE_STR:
+        return RNODE_STR(node)->nd_lit;
       case NODE_INTEGER:
       case NODE_FLOAT:
       case NODE_RATIONAL:
@@ -14974,6 +14973,8 @@ nd_st_key_val(struct parser_params *p, NODE *node)
     switch (nd_type(node)) {
       case NODE_LIT:
         return RNODE_LIT(node)->nd_lit;
+      case NODE_STR:
+        return RNODE_STR(node)->nd_lit;
       case NODE_INTEGER:
         return rb_node_integer_literal_val(node);
       case NODE_FLOAT: