Various renames following the name change from "Runtime APEX" to "ART APEX".

In particular ANDROID_RUNTIME_ROOT is now ANDROID_ART_ROOT.

Test: Build & boot
Test: art/tools/run-gtests.sh in chroot
Test: art/test/testrunner/testrunner.py --target --64 in chroot
Test: art/tools/run-libcore-tests.sh --mode=device --variant=X64 in chroot
Test: art/tools/run-jdwp-tests.sh --mode=device --variant=X64 in chroot
Test: m test-art-host-gtest
Test: art/test/testrunner/testrunner.py --host --64
Test: art/tools/run-jdwp-tests.sh --mode=host
Bug: 135753770
Change-Id: Ia74da964e54cf396d66e9e12ea56da4e9483662a
diff --git a/tools/host_bcp.sh b/tools/host_bcp.sh
index 1dea295..0a78fb4 100755
--- a/tools/host_bcp.sh
+++ b/tools/host_bcp.sh
@@ -59,13 +59,13 @@
     if [[ $USE_FIRST_DIR == true ]]; then
       break
     fi
-    echo "Multiple Runtime apex dirs: ${ART_APEX_SELECTED}, ${d}."
+    echo "Multiple ART APEX dirs: ${ART_APEX_SELECTED}, ${d}."
     exit 1
   fi
   ART_APEX_SELECTED=${d}
 done
 if [[ "x${ART_APEX_SELECTED}" == "x" ]]; then
-  echo "No Runtime apex dir."
+  echo "No ART APEX dir."
   exit 1
 fi