Add two cxx cache directories to cleaned caches in cleanBuild.sh

Bug: b/170640263, b/170611579, b/140447133
Test: cleanBuild.sh bOS passes; cxx dir regenerates; old cxx dir sometimes broke build
Change-Id: I6a830b4f0515f961b8987ada0cbaeefeb4603ef2

diff --git a/cleanBuild.sh b/cleanBuild.sh
index 6e89563..81d3275 100755
--- a/cleanBuild.sh
+++ b/cleanBuild.sh

@@ -67,6 +67,9 @@
   rm -rf .gradle
   rm -rf buildSrc/.gradle
   rm -f local.properties
+  // AGP should (also) do this automatically (b/170640263)
+  rm -rf appsearch/appsearch/.cxx
+  rm -rf appsearch/local-backend/.cxx
   rm -rf $OUT_DIR
 }
 removeCaches