Always store the Prov 4.0 OEM cert in global storage

(This is a merge of http://go/wvgerrit/153550.)

On CE CDM, storage is split between global and per-origin storage, and
one type of storage cannot be used to access the other. (Though, until
an upcoming commit lands, the tests will allow it.) On Android, both
types of storage access the same filesystem. This means that code may
run fine on Android but fail on CE CDM.

The OEM Cert in Provisioning 4.0 is a global file that should only
exist once, but it was being accessed through the per-origin storage,
which would result in a separate OEM Cert being provisioned for each app
& origin on CE CDM. This patch changes the Prov 4.0 code to access it
through the global storage, using techniques similar to how the Usage
Table Header code does this.

Test: x86-64 w/ storage separated
Test: build_and_run_all_unit_tests.sh
Bug: 236400627
Change-Id: I301d250fc9543e62949a4d9fdcbdd109bd941384

libwvdrmengine/cdm/core/test/test_printers.cpp

@@ -991,6 +991,9 @@ void PrintTo(const enum CdmResponseType& value, ::std::ostream* os) {
     case PROVISIONING_4_FAILED_TO_STORE_DRM_CERTIFICATE:
       *os << "PROVISIONING_4_FAILED_TO_STORE_DRM_CERTIFICATE";
       break;
+    case PROVISIONING_4_FAILED_TO_INITIALIZE_DEVICE_FILES_3:
+      *os << "PROVISIONING_4_FAILED_TO_INITIALIZE_DEVICE_FILES_3";
+      break;
     default:
       *os << "Unknown CdmResponseType";
       break;