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

首先查看之前的 pull request 6903、7735、12090 和 12805，然后检查此处汇总的相关 issue。当错误处理程序延迟到 safepoint，使列出的中断相关 bug 和 workaround 不再适用时，这项工作就完成了。