Filter Cast Reciver tests

Merge from Widevine repo of http://go/wvgerrit/169070

This turns on the cast receiver tests for any device that
claims to support this feature. Previously, we had to
explicitly request these tests on the command line.

But since they do not pass for Prov 4.0, we fitler them out
in this case and reference a bug tracking that work.

We also switch to using GTEST_SKIP to skip the tests instead
of modifying the GTEST_FILTER.

Bug: 251240681
Bug: 269310676
Bug: 259455058
Bug: 259454969
Merged from https://widevine-internal-review.googlesource.com/166497

Change-Id: I1bcd749243a474b3f638547aa43c2805e86731af

libwvdrmengine/oemcrypto/test/oec_device_features.cpp

@@ -122,7 +122,6 @@ void DeviceFeatures::Initialize() {
   switch (derive_key_method) {
     case NO_METHOD:
       printf("NO_METHOD: Cannot derive known session keys.\n");
-      // Note: cast_receiver left unchanged because set by user on command line.
       uses_keybox = false;
       loads_certificate = false;
       generic_crypto = false;
@@ -161,7 +160,6 @@ std::string DeviceFeatures::RestrictFilter(const std::string& initial_filter) {
       provisioning_method == OEMCrypto_BootCertificateChain)
                                       FilterOut(&filter, "OEMCryptoLoadsCert*");
   if (!generic_crypto)                FilterOut(&filter, "*GenericCrypto*");
-  if (!cast_receiver)                 FilterOut(&filter, "*CastReceiver*");
   if (!supports_cas)                  FilterOut(&filter, "*CasOnly*");
   if (derive_key_method == NO_METHOD) FilterOut(&filter, "*SessionTest*");
   if (provisioning_method != OEMCrypto_BootCertificateChain)