Change test certificates to use SHA-256.

We're planning to remove support for SHA-1 signatures in TLS
certificates, so change our tests to use SHA-256 signatures instead.

Bug: 77901166
Test: cts -m CtsLibcoreTestCases
Change-Id: I6c85194a88fb9d0582267ed8e6056b593b9e68de
diff --git a/support/src/test/java/libcore/java/security/TestKeyStore.java b/support/src/test/java/libcore/java/security/TestKeyStore.java
index be9874f..691bdf3 100644
--- a/support/src/test/java/libcore/java/security/TestKeyStore.java
+++ b/support/src/test/java/libcore/java/security/TestKeyStore.java
@@ -693,13 +693,13 @@
         String keyAlgorithm = privateKey.getAlgorithm();
         String signatureAlgorithm;
         if (keyAlgorithm.equals("RSA")) {
-            signatureAlgorithm = "sha1WithRSA";
+            signatureAlgorithm = "sha256WithRSA";
         } else if (keyAlgorithm.equals("DSA")) {
-            signatureAlgorithm = "sha1WithDSA";
+            signatureAlgorithm = "sha256WithDSA";
         } else if (keyAlgorithm.equals("EC")) {
-            signatureAlgorithm = "sha1WithECDSA";
+            signatureAlgorithm = "sha256WithECDSA";
         } else if (keyAlgorithm.equals("EC_RSA")) {
-            signatureAlgorithm = "sha1WithRSA";
+            signatureAlgorithm = "sha256WithRSA";
         } else {
             throw new IllegalArgumentException("Unknown key algorithm " + keyAlgorithm);
         }