Sync boost/context assembly files for fibers

Fixes GH-10398

The stack was misaligned upon entering the trampoline function [1], this
causes a CPU trap when the SSE instruction i

Sync boost/context assembly files for fibers

Fixes GH-10398

The stack was misaligned upon entering the trampoline function [1], this
causes a CPU trap when the SSE instruction is executed to copy data from
the stack. This was fixed upstream [2]. This commit syncs all upstream
changes from the boost/context assembly files to our copy.

[1] https://github.com/php/php-src/pull/10407#issuecomment-1404180877
[2] https://github.com/boostorg/context/pull/219

Closes GH-10407.

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Add IBT support for fiber

Indirect Branch Tracking (IBT) is part of Intel's Control-Flow
Enforcement Technology (CET). IBT is hardware based, forward edge
Control-Flow-Integrity mech

Add IBT support for fiber

Indirect Branch Tracking (IBT) is part of Intel's Control-Flow
Enforcement Technology (CET). IBT is hardware based, forward edge
Control-Flow-Integrity mechanism where any indirect CALL/JMP must target
an ENDBR instruction or suffer #CP.

This commit adds IBT support for fiber:
1. Add endbr32/64 in assembly
2. Inform compiler jump_fcontext may return via indirect branch

Furthermore:
gcc support CET since v8.1 and set it to default since gcc 11. That is,
the ELF header of sapi/cli/php has a property named IBT. However, such
property is lost since PHP8.1 because the assembly introduced by Fiber.
This commit also fixes this.

Closes GH-8339

Signed-off-by: Chen, Hu <hu1.chen@intel.com>
Co-authored-by: Christoph M. Becker <cmbecker69@gmx.de>

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Implement Fibers

RFC: https://wiki.php.net/rfc/fibers

Closes GH-6875.