Add test for testing the arch variant cflags set on cc moduled included in APEXes. The code in this CL is copied from Jin's comments at https://android-review.git.corp.google.com/c/platform/build/soong/+/2350557/comment/5755a88b_8c8bfecf/ Bug: 258422889 Test: b test --config=android //build/bazel/rules/apex:apex_tests Change-Id: I80ba8726cd2f360ea5cae7a394d980146e02e8e0