Merge bitcoin/bitcoin#23208: util: Add mremap syscall to AllowAddressSpaceAccess

fab360a util: Add mremap syscall to AllowAddressSpaceAccess (MarcoFalke)

Pull request description:

  Fixes bitcoin/bitcoin#23206

ACKs for top commit:
  practicalswift:
    cr ACK fab360a
  laanwj:
    Code review ACK fab360a
  fanquake:
    ACK fab360a - confirmed that the GUIX build is working with this change:

Tree-SHA512: 9cf808b3e04830e87bca49b27914993929be3c27eb674d89739b8ea5e5c848c87713d638506c1cd2b80b0129c3dff0c488eb240eef3bbf3d7508ece3c934fb54

Author: fanquake

src/util/syscall_sandbox.cpp

@@ -523,14 +523,15 @@ class SeccompPolicyBuilder
 
     void AllowAddressSpaceAccess()
     {
-        allowed_syscalls.insert(__NR_brk);     // change data segment size
-        allowed_syscalls.insert(__NR_madvise); // give advice about use of memory
+        allowed_syscalls.insert(__NR_brk);        // change data segment size
+        allowed_syscalls.insert(__NR_madvise);    // give advice about use of memory
         allowed_syscalls.insert(__NR_membarrier); // issue memory barriers on a set of threads
-        allowed_syscalls.insert(__NR_mlock);    // lock memory
-        allowed_syscalls.insert(__NR_mmap);     // map files or devices into memory
-        allowed_syscalls.insert(__NR_mprotect); // set protection on a region of memory
-        allowed_syscalls.insert(__NR_munlock);  // unlock memory
-        allowed_syscalls.insert(__NR_munmap);   // unmap files or devices into memory
+        allowed_syscalls.insert(__NR_mlock);      // lock memory
+        allowed_syscalls.insert(__NR_mmap);       // map files or devices into memory
+        allowed_syscalls.insert(__NR_mprotect);   // set protection on a region of memory
+        allowed_syscalls.insert(__NR_mremap);     // remap a file in memory
+        allowed_syscalls.insert(__NR_munlock);    // unlock memory
+        allowed_syscalls.insert(__NR_munmap);     // unmap files or devices into memory
     }
 
     void AllowEpoll()