Revert "Use java prebuilts"

This reverts commit 193175094081e9cc3c44e2b3ee290195b1b89613.

Change-Id: I7a99fd6c53d35a2a674f2d60b113a727f3c453ce
diff --git a/core/find-jdk-tools-jar.sh b/core/find-jdk-tools-jar.sh
new file mode 100755
index 0000000..ac0b3b6
--- /dev/null
+++ b/core/find-jdk-tools-jar.sh
@@ -0,0 +1,20 @@
+#!/bin/sh
+if [ "x$ANDROID_JAVA_HOME" != x ] && [ -e "$ANDROID_JAVA_HOME/lib/tools.jar" ] ; then
+    echo $ANDROID_JAVA_HOME/lib/tools.jar
+else
+    JAVAC=$(realpath $(which javac) 2>/dev/null)
+    if [ -z "$JAVAC" ]; then
+        JAVAC=$(readlink -f $(which javac) 2>/dev/null)
+    fi
+    if [ -z "$JAVAC" ]; then
+        JAVAC=$(which javac)
+    fi
+    if [ -z "$JAVAC" ] ; then
+        exit 1
+    fi
+    while [ -L "$JAVAC" ] ; do
+        LSLINE=$(ls -l "$JAVAC")
+        JAVAC=$(echo -n "$LSLINE" | sed -e "s/.* -> //")
+    done
+    echo $JAVAC | sed -e 's:\(.*\)/javac$:\1/../lib/tools.jar:'
+fi