run-test: Fix bash warning with DESUGAR=false

Bash doesn't like missing space before end of ].

Test: DESUGAR=false art/test/testrunner.py --host
Change-Id: I43e500f4f02fb9797be2677e4196f1dda173cec1
diff --git a/test/run-test b/test/run-test
index 1b6df16..bf2d1ec 100755
--- a/test/run-test
+++ b/test/run-test
@@ -92,7 +92,7 @@
 export JACK="$JACK -g -cp $JACK_CLASSPATH"
 
 # Allow changing DESUGAR script to something else, or to disable it with DESUGAR=false.
-if [ -z "$DESUGAR"]; then
+if [ -z "$DESUGAR" ]; then
   export DESUGAR="$ANDROID_BUILD_TOP/art/tools/desugar.sh"
 fi