Revert "installd: Fix set dex2oat to background after boot_complete"

This reverts commit c919183ba4fafcf2e92f6f62d25ee930f62bb0bb.

Reason for revert: Potential culprit of  DeviceBootTest.DeviceBootTest#SELinuxUncheckedDenialBootTest

Change-Id: I17b601364308bcf074cc2f2390f51e099c338765
diff --git a/cmds/installd/dexopt.cpp b/cmds/installd/dexopt.cpp
index 65fc46e..594880a 100644
--- a/cmds/installd/dexopt.cpp
+++ b/cmds/installd/dexopt.cpp
@@ -1818,13 +1818,10 @@
 
     pid_t pid = fork();
     if (pid == 0) {
-        // Need to set schedpolicy before dropping privileges
-        // for cgroup migration. See details at b/175178520.
-        SetDex2OatScheduling(boot_complete);
-
         /* child -- drop privileges before continuing */
         drop_capabilities(uid);
 
+        SetDex2OatScheduling(boot_complete);
         if (flock(out_oat.fd(), LOCK_EX | LOCK_NB) != 0) {
             PLOG(ERROR) << "flock(" << out_oat.path() << ") failed";
             _exit(DexoptReturnCodes::kFlock);