[Darwin] Exclude interception union tests on Darwin and Android

[bruno]

Summary

Since the directory is empty on Darwin, disable the inclusion and avoid the warning below. Exclude on Android as well to match the behavior from lib/interception/tests/CMakeLists.txt

lit.py: /Users/buildslave/jenkins/sharedspace/clang-R_master@2/llvm/utils/lit/lit/discovery.py:224:
warning: input '/Users/buildslave/jenkins/sharedspace/clang-R_master@2/clang-build/Build/tools/clang/runtime/compiler-rt-bins/test/interception/Unit'
contained no tests

This fixes the above warning in some of public bots, like http://lab.llvm.org:8080/green/job/clang-stage2-configure-Rlto_check/8686

[etienneb]

lgtm

(sorry, I wasn't able to jump back on this issue. I ordered a Mac, and I'm still waiting for it).

[bruno]

Thanks Etienne,

Committed r277692.

test/interception/CMakeLists.txt

 set(INTERCEPTION_TEST_DEPS ${SANITIZER_COMMON_LIT_TEST_DEPS})
 set(INTERCEPTION_TESTSUITES)
 
-# Unit tests.
-if(COMPILER_RT_INCLUDE_TESTS)
+# Unit tests. There are currently no unit tests capable to run on Apple or
+# Android targets.
+if(COMPILER_RT_INCLUDE_TESTS AND NOT ANDROID AND NOT APPLE)
   configure_lit_site_cfg(
     ${CMAKE_CURRENT_SOURCE_DIR}/Unit/lit.site.cfg.in
     ${CMAKE_CURRENT_BINARY_DIR}/Unit/lit.site.cfg)