Revert "Ensure only com.android.shell can run in the shell domain."

The following error is occurring on master:

10-23 16:24:24.785 shell  4884  4884 E SELinux : seapp_context_lookup:  No match for app with uid 2000, seinfo platform, name com.google.android.traceur
10-23 16:24:24.785 shell  4884  4884 E SELinux : selinux_android_setcontext:  Error setting context for app with uid 2000, seinfo platform:targetSdkVersion=23:complete: Success
10-23 16:24:24.785 shell  4884  4884 E Zygote  : selinux_android_setcontext(2000, 0, "platform:targetSdkVersion=23:complete", "com.google.android.traceur") failed
10-23 16:24:24.785 shell  4884  4884 F zygote64: jni_internal.cc:593] JNI FatalError called: frameworks/base/core/jni/com_android_internal_os_Zygote.cpp:648: selinux_android_setcontext failed
10-23 16:24:24.818 shell  4884  4884 F zygote64: runtime.cc:535] Runtime aborting...

Bug: 68126425
Bug: 68032516

This reverts commit 714ee5f2.

Change-Id: I7356c4e4facb1e532bfdeb575acf2d83761a0852