testing/tcl_commands: test target create, cget, configure

Introduce basic testing of error-handling in target configuration
related commands.

The tests can be run via `make check` when JTAG `dummy` adapter is
enabled.

Change-Id: Id0f382046dd70007d8e696d82d2396a7ccab7a33
Signed-off-by: Evgeniy Naydanov <evgeniy.naydanov@syntacore.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/8644
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

testing/tcl_commands/Makefile.am

@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+TESTS =
+
+if DUMMY
+TESTS += \
+	test-target-create-command.cfg \
+	test-target-configure-cget-command.cfg
+endif
+
+EXTRA_DIST = utils.tcl $(TESTS)
+
+TEST_EXTENSIONS = .cfg
+CFG_LOG_COMPILER = $(top_builddir)/src/openocd
+AM_CFG_LOG_FLAGS = -f $(abs_srcdir)/utils.tcl -f