Improve debug output of differential fuzzing

[Robbepop]

Using the new FuzzInput struct we now have properly supported Debug output on detected fuzzing failure test cases.

• This debug output shows the chosen Wasm runtime oracle, the wasm_smith module configuration and the Wasm source as .wat source code.
• In contrast to the already implemented crash-inputs feature this information is properly displayed on CI consoles.

Example

Failing input:

        fuzz/artifacts/differential/crash-ec8b55496c8cf9fd654f076239bf3f25d37e6a43

Output of `std::fmt::Debug`:

        FuzzInput {
            chosen_oracle: Wasmtime,
            module: Module {
                config: Config {
                    available_imports: None,
                    exports: None,
                    allow_start_export: true,
                    allowed_instructions: InstructionKinds(
                        FlagSet(NumericInt | Numeric | VectorInt | Vector | Reference | Parametric | Variable | Table | MemoryInt | Memory | Control | Aggregate),
                    ),
                    allow_floats: true,
                    bulk_memory_enabled: true,
                    canonicalize_nans: true,
                    disallow_traps: false,
                    exceptions_enabled: false,
                    export_everything: true,
                    gc_enabled: false,
                    custom_page_sizes_enabled: false,
                    generate_custom_sections: false,
                    max_aliases: 1000,
                    max_components: 10,
                    max_data_segments: 10,
                    max_element_segments: 253,
                    max_elements: 973,
                    max_exports: 297,
                    max_funcs: 740,
                    max_globals: 910,
                    max_imports: 70,
                    max_instances: 10,
                    max_instructions: 917,
                    max_memories: 25,
                    max_memory32_bytes: 1040383744,
                    max_memory64_bytes: 0,
                    max_modules: 10,
                    max_nesting_depth: 10,
                    max_table_elements: 183033,
                    max_tables: 1,
                    max_tags: 0,
                    max_type_size: 1000,
                    max_types: 507,
                    max_values: 10,
                    memory64_enabled: false,
                    memory_max_size_required: false,
                    memory_offset_choices: MemoryOffsetChoices(
                        90,
                        9,
                        1,
                    ),
                    min_data_segments: 0,
                    min_element_segments: 0,
                    min_elements: 0,
                    min_exports: 0,
                    min_funcs: 0,
                    min_globals: 0,
                    min_imports: 0,
                    min_memories: 0,
                    min_tables: 0,
                    min_tags: 0,
                    min_types: 0,
                    min_uleb_size: 0,
                    multi_value_enabled: true,
                    reference_types_enabled: false,
                    relaxed_simd_enabled: false,
                    saturating_float_to_int_enabled: true,
                    sign_extension_ops_enabled: true,
                    shared_everything_threads_enabled: false,
                    simd_enabled: false,
                    tail_call_enabled: true,
                    table_max_size_required: false,
                    threads_enabled: false,
                    allow_invalid_funcs: false,
                    wide_arithmetic_enabled: false,
                    extended_const_enabled: true,
                },
                ...: "...",
            },
            wasm: 
            (module
              (type (;0;) (func))
              (global (;0;) (mut i32) i32.const 1000)
              (export "" (func 0))
              (func (;0;) (type 0)
                global.get 0
                i32.eqz
                if ;; label = @1
                  unreachable
                end
                global.get 0
                i32.const 1
                i32.sub
                global.set 0
              )
            )
            ,
        }

Reproduce with:

        cargo fuzz run -O --features=differential differential fuzz/artifacts/differential/crash-ec8b55496c8cf9fd654f076239bf3f25d37e6a43

Minimize test case with:

        cargo fuzz tmin -O --features=differential differential fuzz/artifacts/differential/crash-ec8b55496c8cf9fd654f076239bf3f25d37e6a43

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Error: Fuzz target exited with exit status: 77