EDK: Split the mojo_edk_system_unittests target.

mojo/edk/system/BUILD.gn

Index: mojo/edk/system/BUILD.gn
diff --git a/mojo/edk/system/BUILD.gn b/mojo/edk/system/BUILD.gn
index 11ae195598f59b654c135cf5d20206233acfa2b7..c6cebeb59f0d588e0bdd9e3a665406e87a243fa3 100644
--- a/mojo/edk/system/BUILD.gn
+++ b/mojo/edk/system/BUILD.gn
@@ -127,14 +127,6 @@ component("system") {
   allow_circular_includes_from = [ "../embedder" ]
 }
 
-group("tests") {
-  testonly = true
-  deps = [
-    ":mojo_edk_system_perftests",
-    ":mojo_edk_system_unittests",
-  ]
-}
-
 mojo_edk_unittests("mojo_edk_system_unittests") {
   sources = [
     # TODO(vtl): This should be in its own mojo_edk_unittests target.
@@ -186,11 +178,6 @@ mojo_edk_unittests("mojo_edk_system_unittests") {
   ]
 
   mojo_edk_deps = [
-    # TODO(vtl): Add separate mojo_edk_unittests targets for these.
-    "mojo/edk/embedder:unittests",
-    "mojo/edk/system/test:unittests",
-    "mojo/edk/util:unittests",
-
     "mojo/edk/system/test",
     "mojo/edk/test:test_support",
     "mojo/edk/util",