Expose some SystemApis and edit framework-cellbroadcast-shared-srcs

The APIs are used in the CellBroadcastService, and the
framework-cellbroadcast-shared-srcs library is also linked there.

Bug: 135956699
Test: manual
Change-Id: I5e71ea1ee1a858c0520c241dc7365733441e0f50
diff --git a/Android.bp b/Android.bp
index c74b458..abae0bd 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1631,8 +1631,10 @@
 filegroup {
     name: "framework-cellbroadcast-shared-srcs",
     srcs: [
+        "core/java/android/os/HandlerExecutor.java",
         "core/java/android/util/LocalLog.java",
-        "core/java/android/util/Slog.java",
+        "core/java/com/android/internal/util/IState.java",
+        "core/java/com/android/internal/util/Preconditions.java",
         "core/java/com/android/internal/util/State.java",
         "core/java/com/android/internal/util/StateMachine.java",
     ],