Use explicit newline with keystore stdin test (elastic#127094)

The add string keystore command accepts input on stdin. In this case,
the terminal is responsible for separating input by newlines that are
system dependent. The mock terminal normally adds the system dependent
newline. However, we also have tests that ensure both unix and windows
style newlines are tested explicitly. This commit fixes the windows
style carriage returns to explicitly contain a newline.

closes elastic#127089

Author: rjernst

distribution/tools/keystore-cli/src/test/java/org/elasticsearch/cli/keystore/AddStringKeyStoreCommandTests.java

@@ -193,7 +193,7 @@ public void testStdinInputWithCarriageReturn() throws Exception {
         String password = "keystorepassword";
         KeyStoreWrapper.create().save(env.configDir(), password.toCharArray());
         terminal.addSecretInput(password);
-        terminal.addSecretInput("Typedthisandhitenter\r");
+        terminal.addSecretInput("Typedthisandhitenter\r\n");
         execute("-x", "foo");
         assertSecureString("foo", "Typedthisandhitenter", password);
     }