gdb/mi: Add -symbol-info-modules command

gdb/mi: Add -symbol-info-modules command

Add '-symbol-info-modules', an MI version of the CLI 'info modules'
command.

gdb/ChangeLog:

	* mi/mi-cmds.c (mi_cmds): Add 'symbol-info-modules' entry.
	* mi/mi-cmds.h (mi_cmd_symbol_info_modules): Declare.
	* mi/mi-symbol-cmds.c (mi_cmd_symbol_info_modules): New function.
	* NEWS: Mention new MI command.

gdb/testsuite/ChangeLog:

	* gdb.mi/mi-fortran-modules-2.f90: New file.
	* gdb.mi/mi-fortran-modules.exp: New file.
	* gdb.mi/mi-fortran-modules.f90: New file.

gdb/doc/ChangeLog:

	* doc/gdb.texinfo (GDB/MI Symbol Query): Document new MI command
	-symbol-info-modules.

Change-Id: Ibc618010d1d5f36ae8a8baba4fb9d9d724e62b0f