fix: UB in SchemaValidator::Double when casting out-of-range doubles

[KowalskiThomas]

What is this PR?

This PR fixes an undefined behaviour happening when trying to cast a double to an integer (int64_t or uint64_t) outside its valid range.

/home/user/rapidjson/include/rapidjson/schema.h:345:50: runtime error: 1e+33 is outside the range of representable values of type 'unsigned long'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /home/user/rapidjson/include/rapidjson/schema.h:345:50 in
MS: 4 ChangeByte-ChangeByte-InsertRepeatedBytes-CrossOver-; base unit: d06ccadf2965827126a941a193346fc522f20a85

The proposed fix is to set the integer representation to 0 if it's outside the valid value range.

The PR also adds a test validating the new behaviour.

[tencent-adm]

All committers have signed the CLA.