Rename abazel() to bazel(), give a warning if clobbering an existing Bazel, and have it call tools/bazel (aka build/bazel/bazel.sh) to start Bazel.

Test: Manually.
Change-Id: I5605571147db33c6b6a008cedbf279bb909ecdee
diff --git a/envsetup.sh b/envsetup.sh
index 82c4565..aa90b4d 100644
--- a/envsetup.sh
+++ b/envsetup.sh
@@ -318,7 +318,7 @@
     #export HOST_EXTRACFLAGS="-I "$T/system/kernel_headers/host_include
 }
 
-function abazel()
+function bazel()
 {
     local T="$(gettop)"
     if [ ! "$T" ]; then
@@ -326,49 +326,12 @@
         return
     fi
 
-    case $(uname -s) in
-        Darwin)
-            ANDROID_BAZEL_PATH="${T}/prebuilts/bazel/darwin-x86_64/bazel"
-            ANDROID_BAZELRC_PATH="${T}/build/bazel/darwin.bazelrc"
-            ANDROID_BAZEL_JDK_PATH="${T}/prebuilts/jdk/jdk11/darwin-x86"
-            ;;
-        Linux)
-            ANDROID_BAZEL_PATH="${T}/prebuilts/bazel/linux-x86_64/bazel"
-            ANDROID_BAZELRC_PATH="${T}/build/bazel/linux.bazelrc"
-            ANDROID_BAZEL_JDK_PATH="${T}/prebuilts/jdk/jdk11/linux-x86"
-            ;;
-        *)
-            ANDROID_BAZEL_PATH=
-            ANDROID_BAZELRC_PATH=
-            ANDROID_BAZEL_JDK_PATH=
-            ;;
-    esac
-
-    if [ -n "$ANDROID_BAZEL_PATH" -a -f "$ANDROID_BAZEL_PATH" ]; then
-        export ANDROID_BAZEL_PATH
-    else
-        echo "Couldn't locate Bazel binary"
-        return
+    if which bazel &>/dev/null; then
+        echo "NOTE: bazel() function sourced from envsetup.sh is being used instead of $(which bazel)"
+        echo
     fi
 
-    if [ -n "$ANDROID_BAZELRC_PATH" -a -f "$ANDROID_BAZELRC_PATH" ]; then
-        export ANDROID_BAZELRC_PATH
-    else
-        echo "Couldn't locate bazelrc file for Bazel"
-        return
-    fi
-
-    if [ -n "$ANDROID_BAZEL_JDK_PATH" -a -d "$ANDROID_BAZEL_JDK_PATH" ]; then
-        export ANDROID_BAZEL_JDK_PATH
-    else
-        echo "Couldn't locate JDK to use for Bazel"
-        return
-    fi
-
-    echo "WARNING: Bazel support for the Android Platform is experimental and is undergoing development."
-    echo "WARNING: Currently, build stability is not guaranteed. Thank you."
-    echo
-    "${ANDROID_BAZEL_PATH}" --server_javabase="${ANDROID_BAZEL_JDK_PATH}" --bazelrc="${ANDROID_BAZELRC_PATH}" "$@"
+    "$T/tools/bazel" "$@"
 }
 
 function printconfig()