fix rust 1.94 ambiguous panic macro warnings

```
error: `panic` is ambiguous
   --> src/./alg_tests.rs:699:26
    |
699 |             unhandled => panic!("extend der2text for tag 0x{unhandled:x?}"),
    |                          ^^^^^ ambiguous name
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #147319 <rust-lang/rust#147319>
    = note: ambiguous because of a conflict between a name from a glob import and an outer scope during import or macro resolution
```

Author: cpu

src/alg_tests.rs

@@ -14,6 +14,7 @@
 
 #![allow(clippy::duplicate_mod)]
 
+use std::panic;
 use std::prelude::v1::*;
 
 use base64::{Engine as _, engine::general_purpose};

src/cert.rs

@@ -424,6 +424,7 @@ mod tests {
     use super::*;
     #[cfg(feature = "alloc")]
     use crate::crl::RevocationReason;
+    use std::panic;
     use std::prelude::v1::*;
 
     #[test]

src/crl/types.rs

@@ -944,7 +944,7 @@ mod tests {
 
     use pki_types::CertificateDer;
     use std::prelude::v1::*;
-    use std::println;
+    use std::{panic, println};
 
     use super::*;
     use crate::cert::Cert;