[gdb] Add maint selftest -verbose option

The print_one_insn selftest in gdb/disasm-selftests.c contains:
...
  /* If you want to see the disassembled instruction printed to gdb_stdout,
     set verbose to true.  */
  static const bool verbose = false;
...

Make this parameter available in the maint selftest command using a new option
-verbose, such that we can do:
...
(gdb) maint selftest -verbose print_one_insn
...

Tested on x86_64-linux.

1 files changed, 3 insertions, 2 deletions

diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 3eafcfb..bf731a1 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -39433,11 +39433,12 @@ data structures, including its flags and contained types.
 
 @kindex maint selftest
 @cindex self tests
-@item maint selftest @r{[}@var{filter}@r{]}
+@item maint selftest @r{[}-verbose@r{]} @r{[}@var{filter}@r{]}
 Run any self tests that were compiled in to @value{GDBN}.  This will
 print a message showing how many tests were run, and how many failed.
 If a @var{filter} is passed, only the tests with @var{filter} in their
-name will be ran.
+name will be ran.  If @code{-verbose} is passed, the self tests can be
+more verbose.
 
 @kindex maint info selftests
 @cindex self tests