Close session before terminate

Merge from the widevine repo of http://go/wvgerrit/16362

A test class holds a default session that it expects to be able to
close in the tear down.  This was not true in the TimingTest because
it calls OEMCrypto_Terminate which closes all open sessions.

This CL closes the default session, and then reopens it again after
OEMCrypto_Initialize.

Change-Id: Ib4128ec3c0a33794c03aa934174cb6fff448483e

libwvdrmengine/oemcrypto/test/oemcrypto_test.cpp

@@ -5495,10 +5495,13 @@ TEST_F(UsageTableTest, TimingTest) {
 
   sleep(kLongSleep);
   // This is as close to reboot as we can simulate in code.
+  ASSERT_NO_FATAL_FAILURE(session_.close());  // Close sessions before terminate.
   OEMCrypto_Terminate();
   sleep(kShortSleep);
   OEMCrypto_Initialize();
   EnsureTestKeys();
+  // Test teardown expects session_ to be open.
+  ASSERT_NO_FATAL_FAILURE(session_.open());
 
   // After a reboot, we should be able to reload keys, and generate reports.
   sleep(kLongSleep);