Centralize printing "<optimized out>".
    
    	gdb/
    	* valprint.h (val_print_optimized_out): Declare.
    	* cp-valprint.c (cp_print_value_fields): Use
    	val_print_optimized_out.
    	* jv-valprint.c (java_print_value_fields): Ditto.
    	* p-valprint.c (pascal_object_print_value_fields): Ditto.
    	* printcmd.c (print_formatted): Ditto.
    	* valprint.c (valprint_check_validity): Ditto.
    	(value_check_printable): Ditto.
    	(val_print_optimized_out): New.
    
    	gdb/doc/
    	* gdb.texinfo: s/value optimized out/optimized out/g
    
    	gdb/testsuite/
    	* gdb.base/frame-args.exp: Adjust.
    	* gdb.dwarf2/dw2-noloc.exp: Adjust.
    	* gdb.dwarf2/dw2-inline-param.exp: Adjust.
    	* gdb.dwarf2/pieces.exp: Adjust.
    	* gdb.opt/clobbered-registers-O2.exp: Adjust.
    	* gdb.opt/inline-locals.exp: Adjust.
    	* gdb.threads/fork-child-threads.exp: Adjust.