Make sure $BAZEL is set when `./compile.sh test` is run

Fixes #832.

--
MOS_MIGRATED_REVID=113537330
diff --git a/compile.sh b/compile.sh
index 880555d..bf13174 100755
--- a/compile.sh
+++ b/compile.sh
@@ -68,6 +68,8 @@
   display "$INFO    $0 ${COMMANDS} /path/to/bazel"
   new_step 'Building Bazel from scratch'
   source scripts/bootstrap/compile.sh
+  # The DO_COMPILE flow will actually create the bazel binary and set BAZEL.
+  DO_COMPILE=1
 fi
 
 #