fuzz: replace every fuzzer-controlled loop with a LIMITED_WHILE loop

Blindly chose a cap of 10000 iterations for every loop, except for
the two in script_ops.cpp and scriptnum_ops.cpp which appeared to
(sometimes) be deserializing individual bytes; capped those to one
million to ensure that sometimes we try working with massive scripts.

There was also one fuzzer-controlled loop in timedata.cpp which was
already capped, so I left that alone.

git grep 'while (fuzz' should now run clean except for timedata.cpp

src/test/fuzz/crypto_aes256.cpp

@@ -19,7 +19,7 @@ FUZZ_TARGET(crypto_aes256)
     AES256Encrypt encrypt{key.data()};
     AES256Decrypt decrypt{key.data()};
 
-    while (fuzzed_data_provider.ConsumeBool()) {
+    LIMITED_WHILE(fuzzed_data_provider.ConsumeBool(), 10000) {
         const std::vector<uint8_t> plaintext = ConsumeFixedLengthByteVector(fuzzed_data_provider, AES_BLOCKSIZE);
         std::vector<uint8_t> ciphertext(AES_BLOCKSIZE);
         encrypt.Encrypt(ciphertext.data(), plaintext.data());