Share *_OUT_TESTCASES environment variables with TF

Instead of having test tools search the OUT_DIR for the
testcases folders (of which there can be multiple different
targets), let's have these variables become part of the runtime
environment after a developer has run lunch.

Bug: 35322559
Test: . build/envsetup.sh ; lunch ; printenv | grep TESTCASES
Change-Id: Ic4addc2b9727ff717b2e595b9be224650e2f1b1d
diff --git a/envsetup.sh b/envsetup.sh
index 710b28f..b239441 100644
--- a/envsetup.sh
+++ b/envsetup.sh
@@ -260,6 +260,12 @@
     unset ANDROID_HOST_OUT
     export ANDROID_HOST_OUT=$(get_abs_build_var HOST_OUT)
 
+    unset ANDROID_HOST_OUT_TESTCASES
+    export ANDROID_HOST_OUT_TESTCASES=$(get_abs_build_var HOST_OUT_TESTCASES)
+
+    unset ANDROID_TARGET_OUT_TESTCASES
+    export ANDROID_TARGET_OUT_TESTCASES=$(get_abs_build_var TARGET_OUT_TESTCASES)
+
     # needed for building linux on MacOS
     # TODO: fix the path
     #export HOST_EXTRACFLAGS="-I "$T/system/kernel_headers/host_include