Invalid perl syntax should result in failure when #strictFeatures
is enabled.
#strictFeatures

-- schema.json --
{
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "pattern": "^(?![ \\t\\n]*\\(default(.*)\\))[\\s\\S]*"
}
-- out/decode/extract --
ERROR:
unsupported Perl regexp syntax in "^(?![ \\t\\n]*\\(default(.*)\\))[\\s\\S]*": error parsing regexp: invalid or unsupported Perl syntax: `(?!`:
    schema.json:3:6
