All "numeric" strings which emitted a notice now emit the usual warning.

…ing offset

…d as string offset"
As the secondary vote for this is failing
This reverts commit a835d27b31185688053a79eac59650a70eb97060.

RFC: https://wiki.php.net/rfc/saner-numeric-strings
This removes the -1 allow_error mode from is_numeric_string functions and replaces it by
a trailing boolean out argument to preserve BC in a couple of places.
Most of the changes can be resumed to "numeric" strings which emitted a E_NOTICE now emit
a E_WARNING and "numeric" strings which emitted a E_WARNING now throw a TypeError.
This mostly affects:
 - String offsets
 - Arithmetic operations
 - Bitwise operations
Closes phpGH-5762