explain: Add support for the new exec log format

cli/explain/compactgraph/BUILD.bazel

@@ -19,12 +19,16 @@ go_library(
 
 go_test(
     name = "compactgraph_test",
-    srcs = ["compactgraph_test.go"],
+    srcs = [
+        "compactgraph_test.go",
+        "input_test.go",
+    ],
     data = [
         "//cli/explain/compactgraph/testdata:all_logs",
     ],
+    embed = [":compactgraph"],
+    race = "on",
     deps = [
-        ":compactgraph",
         "//proto:spawn_diff_go_proto",
         "//proto:spawn_go_proto",
         "@com_github_stretchr_testify//assert",