kata-env: Fix amd64 VM container capable check

Fix nasty bug which resulted in `kata-env` showing
`VMContainerCapable = true` even on amd64 systems without virtualisation
support (thankfully `kata-check` still showed the correct results).

Added arch-specific tests to avoid any possibility of regression.

Fixes #660.

Signed-off-by: James O. D. Hunt <james.o.hunt@intel.com>

cli/kata-check_arm64_test.go

@@ -198,3 +198,7 @@ foo     : bar
 		}
 	}
 }
+
+func TestSetCPUtype(t *testing.T) {
+	testSetCPUTypeGeneric(t)
+}