Delaying error handlers

Description

Due to error handlers, some operations may have unsuspected effects. This is the cause of bugs and workarounds. Quoting GH-6903:

[...] long-standing source of interrupt
vulnerabilities: A notice is emitted during execution of an opcode,
resulting in an error handling being run. The error handler modifies
some data structure the opcode is working on, resulting in UAF or
other memory corruption.

These bugs and workarounds could be avoided by delaying error handlers until a safepoint. Existing/Previous work:

• https://github.com/php/php-src/pull/6903
• https://github.com/php/php-src/pull/7735
• https://github.com/php/php-src/pull/12090
• https://github.com/php/php-src/pull/12805

I'm creating this ticket to aggregate issues that would not exist with delayed error handlers:

• https://github.com/php/php-src/issues/13754
• https://github.com/php/php-src/issues/15907
• https://github.com/php/php-src/issues/16726
• https://github.com/php/php-src/issues/17416
• https://github.com/php/php-src/issues/18043
• https://github.com/php/php-src/issues/18274
• https://github.com/php/php-src/issues/20042
• https://github.com/php/php-src/issues/20482
• https://github.com/php/php-src/issues/20855
• https://github.com/php/php-src/issues/21024
• https://github.com/php/php-src/issues/21245

Comienza revisando los pull requests anteriores 6903, 7735, 12090 y 12805, y después examina las issues enlazadas que se agrupan aquí. El trabajo estará completo cuando los manejadores de errores se retrasen hasta un safepoint, de modo que los errores y workarounds relacionados con las interrupciones que se enumeran dejen de aplicarse.