[llvm] [BOLT] Allow missing DT_FINI{,_ARRAY} if instrumentation-sleep-time is used (PR #170086)

[Vasily Leonenko via llvm-commits]

vleonen wrote:

> Thanks for the improvement, looks good.
> 
> Just curious: have you had any use cases where both .fini / .fini_array were missing, if you can share?

E.g. libc:
```
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 20.04.5 LTS
Release:        20.04
Codename:       focal
$ readelf -dW /lib/aarch64-linux-gnu/libc.so.6
Dynamic section at offset 0x15db28 contains 25 entries:
  Tag        Type                         Name/Value
 0x0000000000000001 (NEEDED)             Shared library: [ld-linux-aarch64.so.1]
 0x000000000000000e (SONAME)             Library soname: [libc.so.6]
 0x000000000000000c (INIT)               0x20c88
 0x0000000000000019 (INIT_ARRAY)         0x16abf8
 0x000000000000001b (INIT_ARRAYSZ)       16 (bytes)
 0x0000000000000004 (HASH)               0x157728
 0x000000006ffffef5 (GNU_HASH)           0x2b8
 0x0000000000000005 (STRTAB)             0x115e8
 0x0000000000000006 (SYMTAB)             0x3e48
 0x000000000000000a (STRSZ)              24397 (bytes)
 0x000000000000000b (SYMENT)             24 (bytes)
 0x0000000000000003 (PLTGOT)             0x16dfe8
 0x0000000000000002 (PLTRELSZ)           336 (bytes)
 0x0000000000000014 (PLTREL)             RELA
 0x0000000000000017 (JMPREL)             0x20698
 0x0000000000000007 (RELA)               0x18928
 0x0000000000000008 (RELASZ)             32112 (bytes)
 0x0000000000000009 (RELAENT)            24 (bytes)
 0x000000006ffffffc (VERDEF)             0x18730
 0x000000006ffffffd (VERDEFNUM)          13
 0x000000006ffffffe (VERNEED)            0x188f8
 0x000000006fffffff (VERNEEDNUM)         1
 0x000000006ffffff0 (VERSYM)             0x17536
 0x000000006ffffff9 (RELACOUNT)          1255
 0x0000000000000000 (NULL)               0x0
```

https://github.com/llvm/llvm-project/pull/170086