gdb: Add support for dumping to verilog hex format.

gdb: Add support for dumping to verilog hex format.

Extend the gdb 'dump' command to allow creating output in verilog hex
format.  Add some tests to cover new functionality.  As bfd does not
currently support reading in verilog hex formats the tests only cover
the 'dump' command, not the 'restore' command.

gdb/ChangeLog:

	* cli/cli-dump.c (verilog_cmdlist): New variable.
	(dump_verilog_memory): New function.
	(dump_verilog_value): New function.
	(verilog_dump_command): New function.
	(_initialize_cli_dump): Add new commands to support verilog dump
	format.
	* NEWS: Add entry for "dump verilog".

gdb/doc/ChangeLog:

	* gdb.texinfo (Dump/Restore Files): Add detail about verilog dump
	format.

gdb/testsuite/ChangeLog:

	* gdb.base/dump.exp: Add *.verilog files to all_files list.  Add
	new tests for verilog output.