Revert "Reapply "[sanitize] Don't build older then 1h requests"" (llvm#296)

Reverts llvm#295

Try again according to
llvm#266 (comment)

Author: vitalybuka

zorg/buildbot/builders/sanitizers/buildbot_functions.sh

@@ -144,11 +144,6 @@ function buildbot_update {
       git checkout -f "${BUILDBOT_REVISION}"
       git status
       git rev-list --pretty --max-count=1 HEAD
-      # FIXME: Workaround for https://github.com/llvm/llvm-zorg/issues/250
-      [[ "${SKIP_OLD:-1}" == "0" ]] || [[ ! -v BUILDBOT_SCHEDULER ]] || [[ "${BUILDBOT_SCHEDULER}" == "force-build-scheduler" ]] || (git log -1 --after='3 hours ago' | grep .) || {
-        echo Revision is not recent enough
-        exit 1
-      }
     ) || { build_exception ; exit 1 ; }
     LLVM=$ROOT/llvm-project/llvm
   fi
@@ -209,7 +204,7 @@ function build_clang_at_release_tag {
   then
     echo "@@@BUILD_STEP using pre-built stage1 clang at r${host_clang_revision}@@@"
   else
-    SKIP_OLD=0 BUILDBOT_MONO_REPO_PATH= BUILDBOT_REVISION="${host_clang_revision}" buildbot_update
+    BUILDBOT_MONO_REPO_PATH= BUILDBOT_REVISION="${host_clang_revision}" buildbot_update
 
     rm -rf ${STAGE1_DIR}
     echo @@@BUILD_STEP build stage1 clang at $host_clang_revision@@@