System tests: add podman system check tests

Testing `podman system check` requires that we have a way to
intentionally introduce storage corruptions.  Add a hidden `podman
testing` command that provides the necessary internal logic in
subcommands.  Stub out the tunnel implementation for now.

Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>

Makefile

@@ -238,7 +238,7 @@ binaries: podman podman-remote ## Build podman and podman-remote binaries
 else ifneq (, $(findstring $(GOOS),darwin windows))
 binaries: podman-remote ## Build podman-remote (client) only binaries
 else
-binaries: podman podman-remote podmansh rootlessport quadlet ## Build podman, podman-remote and rootlessport binaries quadlet
+binaries: podman podman-remote podman-testing podmansh rootlessport quadlet ## Build podman, podman-remote and rootlessport binaries quadlet
 endif
 
 # Extract text following double-# for targets, as their description for
@@ -457,6 +457,16 @@ rootlessport: bin/rootlessport
 podmansh: bin/podman
 	if [ ! -f bin/podmansh ]; then ln -s podman bin/podmansh; fi
 
+$(SRCBINDIR)/podman-testing: $(SOURCES) go.mod go.sum
+	$(GOCMD) build \
+		$(BUILDFLAGS) \
+		$(GO_LDFLAGS) '$(LDFLAGS_PODMAN)' \
+		-tags "${BUILDTAGS}" \
+		-o $@ ./cmd/podman-testing
+
+.PHONY: podman-testing
+podman-testing: bin/podman-testing
+
 ###
 ### Secondary binary-build targets
 ###
@@ -877,6 +887,11 @@ ifneq ($(shell uname -s),FreeBSD)
 	install ${SELINUXOPT} -m 644 contrib/tmpfile/podman.conf $(DESTDIR)${TMPFILESDIR}/podman.conf
 endif
 
+.PHONY: install.testing
+install.testing:
+	install ${SELINUXOPT} -d -m 755 $(DESTDIR)$(BINDIR)
+	install ${SELINUXOPT} -m 755 bin/podman-testing $(DESTDIR)$(BINDIR)/podman-testing
+
 .PHONY: install.modules-load
 install.modules-load: # This should only be used by distros which might use iptables-legacy, this is not needed on RHEL
 	install ${SELINUXOPT} -m 755 -d $(DESTDIR)${MODULESLOADDIR}