Fix test_glob_noop_incremental

I6a98660cfe6a40bcaa978e8d7544cdffad86a7fa was submitted concurrently
with test_glob_noop_incremental and broke the test by making the
first build incremental.  Add an rm -rf out to make the test start
from a clean build.

Bug: 185591972
Test: tests/bootstrap_test.sh
Change-Id: I529aaf707b2790e5e1022ba9b2637ed7d2435bd5

tests/bootstrap_test.sh

@@ -124,6 +124,11 @@ EOF
 function test_glob_noop_incremental() {
   setup
 
+  # This test needs to start from a clean build, but setup creates an
+  # initialized tree that has already been built once.  Clear the out
+  # directory to start from scratch.
+  rm -rf out
+
   mkdir -p a
   cat > a/Android.bp <<'EOF'
 python_binary_host {