Remove postinstall unittests root check.

Not all the postinstall tests need to be runned as root. Remove the
global check.

Bug: None
TEST=FEATURES=test emerge-link update_engine

Change-Id: I269e413a26ec84022448e64b34a5ee795b5a6e31
diff --git a/payload_consumer/postinstall_runner_action_unittest.cc b/payload_consumer/postinstall_runner_action_unittest.cc
index 3e7d87a..da5a1d4 100644
--- a/payload_consumer/postinstall_runner_action_unittest.cc
+++ b/payload_consumer/postinstall_runner_action_unittest.cc
@@ -95,8 +95,6 @@
     // stored in the "disk_ext2_unittest.img" image.
     postinstall_image_ =
         test_utils::GetBuildArtifactsPath("gen/disk_ext2_unittest.img");
-
-    ASSERT_EQ(0U, getuid()) << "Run these tests as root.";
   }
 
   void TearDown() override {