Add cram test

The test uses osolo5-elftool on the test_hello application from the
solo5 tests to query their abi and manifest. The manifest is empty and
boring.

dune-project

@@ -1,2 +1,3 @@
 (lang dune 2.9)
 (name solo5-elftool)
+(cram enable)

test/dune

@@ -0,0 +1,7 @@
+(cram
+  (deps
+    test_hello.hvt
+    test_hello.muen
+    test_hello.spt
+    test_hello.virtio
+    test_hello.xen))

test/osolo5-elftool.t

@@ -0,0 +1,20 @@
+Execute osolo5-elftool on hvt binary
+
+  $ osolo5-elftool query-abi test_hello.hvt
+  { "type": "solo5.abi", "target": "hvt", "version": 2 
+  }
+  $ osolo5-elftool query-manifest test_hello.hvt
+  { "type": "solo5.manifest", "version": 1, "devices": [  ]
+  }
+  $ osolo5-elftool query-abi test_hello.muen
+  { "type": "solo5.abi", "target": "muen", "version": 3 
+  }
+  $ osolo5-elftool query-abi test_hello.spt
+  { "type": "solo5.abi", "target": "spt", "version": 2 
+  }
+  $ osolo5-elftool query-abi test_hello.virtio
+  { "type": "solo5.abi", "target": "virtio", "version": 1 
+  }
+  $ osolo5-elftool query-abi test_hello.xen
+  { "type": "solo5.abi", "target": "xen", "version": 1 
+  }