Do Not Add Parallel Unit Tests

(This is a merge of http://go/wvgerrit/71325)

Widevine CE CDM and the buildbot now have parallel operations unit
tests. These tests are not relevant on Android since it is not possible
to call into the Android CDM from multiple threads. However, there is
one change in CdmEngine that needs to be copied over to Android for
consistency's sake.

Bug: 70889998
Bug: 118584039
Test: Android Build
Change-Id: Iea5df62be256383e832b4fcfbd5ff5090e3f3b03

libwvdrmengine/cdm/core/include/cdm_engine.h

@@ -343,6 +343,7 @@ class CdmEngine {
 
  protected:
   friend class CdmEngineFactory;
+  friend class ParallelCdmTest;
   friend class WvCdmEnginePreProvTest;
   friend class WvCdmTestBase;
   friend class WvGenericOperationsTest;