devel/valgrind-devel: Update 3.25.0.g20250530 => 3.26.0.g2025081

Changelist (from NEWS)

The most important one is 506499 which errors for each run with for CURRENT.

338803 Handling of dwz debug alt files or cross-CU is broken
418756 MAP_FIXED_NOREPLACE mmap flag unsupported
493430 Review all syscalls that use or return (new) file descriptors
493434 Add --track-fds=bad mode (no "leak" tracking)
505673 Valgrind crashes with an internal error and SIGBUS when

the guest tries to open its own file with O_WRONLY|O_CREAT|O_TRUNC

506076 unimplemented fcntl command: 1028 (F_CREATED_QUERY)
506499 Unhandled syscall 592 (exterrctl - FreeBSD
506795 Better report which clone flags are problematic
506806 Fix execveat() with AT_FDCWD and relative path
506813 The execveat wrapper needs to do more checking
506910 openat2 with RESOLVE_NO_MAGICLINKS succeeds on /proc/self/exe
506930 valgrind allows SIGKILL being reset to SIG_DFL
506970 mmap needs an EBADF fd_allowed check
507853 faccessat and faccessat2 should handle AT_FDCWD and absolute paths
507868 futimesat doesn't handle AT_FDCWD
507873 Make fchmodat and fchmodat2 syscall wrappers accept AT_FDCWD
507970 -Wcalloc-transposed-args warnings in valgrind-di-server.c
508029 Review the vmsplice syscall wrapper
508093 VALGRIND_CLO_CHANGE does not update vex_control
508154 PRE(sys_fchownat) not handling VKI_AT_FDCWD

Improve port:

• Replace python:3.9+,run with python:run - python == python:3.9+ now.
• Replace PORTVERSION with DISTVERSION.
• Use parametrization in DISTNAME from DISTVERSION.

PR: 288949