test_bitcoin: fix decorators for running tests twice (#4669)

This bug is triggered if ecc_fast._libsecp256k1 and/or
crypto.AES are not present.

Before, if the first test would have raised an exception
it would have been implicitly caught by returning from
the finally block and hence this effectively masks the
test's outcome. Now, the exception is properly propagated
causing the test to fail if an exception is raised.

electrum/tests/test_bitcoin.py

@@ -48,10 +48,10 @@ def needs_test_with_all_ecc_implementations(func):
             # first test without libsecp
             func(*args, **kwargs)
         finally:
-            # if libsecp is not available, we are done
-            if not ecc_fast._libsecp256k1:
-                return
             ecc_fast.do_monkey_patching_of_python_ecdsa_internals_with_libsecp256k1()
+        # if libsecp is not available, we are done
+        if not ecc_fast._libsecp256k1:
+            return
         # if libsecp is available, test again now
         func(*args, **kwargs)
     return run_test
@@ -74,10 +74,10 @@ def needs_test_with_all_aes_implementations(func):
             # first test without pycryptodomex
             func(*args, **kwargs)
         finally:
-            # if pycryptodomex is not available, we are done
-            if not _aes:
-                return
             crypto.AES = _aes
+        # if pycryptodomex is not available, we are done
+        if not _aes:
+            return
         # if pycryptodomex is available, test again now
         func(*args, **kwargs)
     return run_test