Remove unecessary changes in cobc/tree.c

cobc/ChangeLog

@@ -64,7 +64,7 @@
 2024-02-26  Boris Eng <[email protected]>
 
 	FR #488: thread-safety for string handling using state vars
-	* tree.h (cb_program), tree.c (cb_build_program): new attributes
+	* tree.h (cb_program): new attributes
 	* codegen.c (output_strings_states, codegen_internal, output_data):
 	  added structures for the data used by strings functions as local variables
 	  in the C generated code. Handle CB_TAG_DIRECT in output_data function

cobc/tree.c

@@ -2248,12 +2248,6 @@ cb_build_program (struct cb_program *last_program, const int nest_level)
 			p->flag_recursive = 1;
 		}
 	}
-
-	/* state structure for strings */
-	p->inspect_st = NULL;
-	p->string_st = NULL;
-	p->unstring_st = NULL;
-
 	return p;
 }