Use Strict Directive needs to be preflighted

Found this issue while cleaning up test262 file, not sure if this is possible in meriyah. It’s not a serious bug in real world, as people always put use strict directive at beginning of a scope.

Meriyah rejects following code as per spec:

> parse('"use strict"; "\\1";')
Uncaught:
[ParseError [SyntaxError]: [1:16]: Octal escape sequences are not allowed in strict mode
] {
  index: 16,
  line: 1,
  column: 16,
  description: '[1:16]: Octal escape sequences are not allowed in strict mode',
  loc: { line: 1, column: 16 }
}

But failed to do so if the use strict directive is after the problematic code.

> parse('"\\1"; "use strict";')
{
  type: 'Program',
  sourceType: 'script',
  body: [
    { type: 'ExpressionStatement', expression: [Object] },
    { type: 'ExpressionStatement', expression: [Object] }
  ]
}

[3cp]

I am not going to try, at least for now. This bug has no impact on real world code. It’s just an edge case in the spec. People has no reason to write code like this, rather than testing a parser’s spec compliance.

[3cp]

I will try to decipher ecma spec first. That adjacency is weird.