Remove mojo/go - this is being developed in the mojo repo

mojo/BUILD.gn

Index: mojo/BUILD.gn
diff --git a/mojo/BUILD.gn b/mojo/BUILD.gn
index 4c5a0e675d7a30e08a5acc7203d18685c631801d..02f815707c0deafb7d2681262918de84d1605f7b 100644
--- a/mojo/BUILD.gn
+++ b/mojo/BUILD.gn
@@ -7,9 +7,6 @@ import("//build/config/ui.gni")
 group("mojo") {
   # Meta-target, don't link into production code.
   testonly = true
-  declare_args() {
-    mojo_use_go = false
-  }
   deps = [
     ":tests",
     "//mojo/apps/js:mojo_js_content_handler",
@@ -27,14 +24,6 @@ group("mojo") {
       "//mojo/android",
     ]
   }
-
-  if (is_linux) {
-    if (mojo_use_go) {
-      deps += [
-        "//mojo/go",
-      ]
-    }
-  }
 }
 
 group("tests") {