Remove core.art image

It is no longer used.

Test: ./art/test.py -r --optimizing
Bug: 147817558
Bug: 147819342
Change-Id: I913d7b78365d028bfcd9d876238882ebfd410682
diff --git a/tools/bootjars.sh b/tools/bootjars.sh
index d6882a5..5516bfb 100755
--- a/tools/bootjars.sh
+++ b/tools/bootjars.sh
@@ -73,7 +73,7 @@
   # defined in Android.common_path.mk, otherwise we would just use HOST-/TARGET_TEST_CORE_JARS.
 
   # Note: This must start with the CORE_IMG_JARS in Android.common_path.mk
-  # because that's what we use for compiling the core.art image.
+  # because that's what we use for compiling the boot.art image.
   # It may contain additional modules from TEST_CORE_JARS.
   core_jars_list="core-oj core-libart okhttp bouncycastle apache-xml core-icu4j"
   boot_jars_list=""