Hide Parcel#readSparseIntArray and Parcel#writeSparseIntArray

They were added for a CL that later stopped using them, so there
is no current need for them in public API.

Bug: 35812784
Change-Id: I2a9a30bee65894235f2cc81ab1bd5a37c9296c02
Test: build succeeds
diff --git a/core/java/android/os/Parcel.java b/core/java/android/os/Parcel.java
index 7a39d23..2e35a51 100644
--- a/core/java/android/os/Parcel.java
+++ b/core/java/android/os/Parcel.java
@@ -898,6 +898,9 @@
         }
     }
 
+    /**
+     * @hide
+     */
     public final void writeSparseIntArray(SparseIntArray val) {
         if (val == null) {
             writeInt(-1);
@@ -2323,6 +2326,7 @@
     /**
      * Read and return a new SparseIntArray object from the parcel at the current
      * dataPosition(). Returns null if the previously written array object was null.
+     * @hide
      */
     public final SparseIntArray readSparseIntArray() {
         int N = readInt();