Keystore 2.0 SPI: Fix contract between equals and hashCode 2

This fixes the contract between equals and hashCode in
AndroidKeystorePublicKey. The previous fix made only a reference
comparisson between certificate blobs. In this patch java.util.Arrays is
used to compare and compute the hash of the array.

Bug: 196118021
Test: See following CL.
Change-Id: I2b8b7e740fb377de39fd21f763e15cb00024b2fc

keystore/java/android/security/keystore2/AndroidKeyStorePublicKey.java

@@ -23,7 +23,7 @@ import android.system.keystore2.KeyDescriptor;
 import android.system.keystore2.KeyMetadata;
 
 import java.security.PublicKey;
-import java.util.Objects;
+import java.util.Arrays;
 
 /**
  * {@link PublicKey} backed by Android Keystore.
@@ -62,8 +62,8 @@ public abstract class AndroidKeyStorePublicKey extends AndroidKeyStoreKey implem
         int result = 1;
 
         result = prime * result + super.hashCode();
-        result = prime * result + ((mCertificate == null) ? 0 : mCertificate.hashCode());
-        result = prime * result + ((mCertificateChain == null) ? 0 : mCertificateChain.hashCode());
+        result = prime * result + Arrays.hashCode(mCertificate);
+        result = prime * result + Arrays.hashCode(mCertificateChain);
 
         return result;
     }
@@ -83,7 +83,7 @@ public abstract class AndroidKeyStorePublicKey extends AndroidKeyStoreKey implem
          */
         final AndroidKeyStorePublicKey other = (AndroidKeyStorePublicKey) obj;
 
-        return Objects.equals(mCertificate, other.mCertificate) && Objects.equals(mCertificateChain,
+        return Arrays.equals(mCertificate, other.mCertificate) && Arrays.equals(mCertificateChain,
                 other.mCertificateChain);
     }
 }