Cherry pick 18.4 changes to udc-widevine-dev

Get the udc-widevine-dev Android branch and oemcrypto-v18 cdm branch in
sync. The commit ID for 18.4 on oemcrypto-v18 is
https://widevine-internal.git.corp.google.com/cdm/+/a2f23a2281e5e06dc2867585bdc516fa132b639.

Merged from go/wvgerrit/190151

Bug: 290252845
Test: unit tests passing on Panther device
Change-Id: I63fa3f1c784f737ca1480e5febe4f3f5a8a49948

libwvdrmengine/Android.bp

@@ -216,10 +216,6 @@ cc_library_static {
         "libutils_headers",
     ],
 
-    generated_headers: [
-        "wv_android_build_id",
-    ],
-
     shared_libs: [
         "libbinder_ndk",
         "libcrypto",
@@ -356,23 +352,3 @@ cc_fuzz {
         ],
     },
 }
-
-python_binary_host {
-    name: "wv-android-build-id-gen",
-    srcs: [
-        "wv-android-build-id-gen.py",
-    ],
-    version: {
-        py3: {
-            embedded_launcher: true,
-        },
-    },
-}
-
-genrule {
-    name: "wv_android_build_id",
-    srcs: ["apex/apex_manifest.json"],
-    tools: ["wv-android-build-id-gen"],
-    cmd: "$(location wv-android-build-id-gen) < $(in) > $(out)",
-    out: ["wv_android_build_id.h"],
-}