Don't always zero pad in print_*_chars

Don't always zero pad in print_*_chars

This changes print_octal_chars and print_decimal_chars to never zero
pad, and changes print_binary_chars and print_hex_chars to only
optionally zero-pad, based on a flag.

ChangeLog
2017-06-12  Tom Tromey  <tom@tromey.com>

	PR exp/16225:
	* valprint.h (print_binary_chars, print_hex_chars): Update.
	* valprint.c (val_print_type_code_int): Update.
	(print_binary_chars): Add "zero_pad" argument.
	(emit_octal_digit): New function.
	(print_octal_chars): Don't zero-pad.
	(print_decimal_chars): Likewise.
	(print_hex_chars): Add "zero_pad" argument.
	* sh64-tdep.c (sh64_do_fp_register): Update.
	* regcache.c (regcache::dump): Update.
	* printcmd.c (print_scalar_formatted): Update.
	* infcmd.c (default_print_one_register_info): Update.

2017-06-12  Tom Tromey  <tom@tromey.com>

	PR exp/16225:
	* gdb.reverse/i386-sse-reverse.exp: Update tests.
	* gdb.arch/vsx-regs.exp: Update tests.
	* gdb.arch/s390-vregs.exp (hex128): New proc.
	Update test.
	* gdb.arch/altivec-regs.exp: Update tests.