fuzz: Fix RPC internal bug detection

Author: MarcoFalke

src/test/fuzz/rpc.cpp

@@ -360,7 +360,9 @@ FUZZ_TARGET_INIT(rpc, initialize_rpc)
         rpc_testing_setup->CallRPC(rpc_command, arguments);
     } catch (const UniValue& json_rpc_error) {
         const std::string error_msg{find_value(json_rpc_error, "message").get_str()};
-        if (error_msg.find("Internal bug detected") != std::string::npos) {
+        // Once c++20 is allowed, starts_with can be used.
+        // if (error_msg.starts_with("Internal bug detected")) {
+        if (0 == error_msg.rfind("Internal bug detected", 0)) {
             // Only allow the intentional internal bug
             assert(error_msg.find("trigger_internal_bug") != std::string::npos);
         }

src/util/check.h

@@ -33,11 +33,11 @@ class NonFatalCheckError : public std::runtime_error
     do {                                                          \
         if (!(condition)) {                                       \
             throw NonFatalCheckError(                             \
-                strprintf("%s:%d (%s)\n"                          \
-                          "Internal bug detected: '%s'\n"         \
+                strprintf("Internal bug detected: '%s'\n"         \
+                          "%s:%d (%s)\n"                          \
                           "You may report this issue here: %s\n", \
-                    __FILE__, __LINE__, __func__,                 \
                     (#condition),                                 \
+                    __FILE__, __LINE__, __func__,                 \
                     PACKAGE_BUGREPORT));                          \
         }                                                         \
     } while (false)