[lld][SystemZ] Assertion failure

This is the assembly generated by the C test case in https://github.com/llvm/llvm-project/issues/224008:
```asm
.file "test.cpp"
.text
.globl _Z4testj # -- Begin function _Z4testj
.p2align 1
.prefalign 4, .Lfunc_end0, nop
.type _Z4testj,@function
_Z4testj: # @_Z4testj
# %bb.0: # %entry
lgrl %r1, .L__const._Z4testj.digits@GOT
llgc %r2, 0(%r2,%r1)
br %r14
.Lfunc_end0:
.size _Z4testj, .Lfunc_end0-_Z4testj
# -- End function
.type .L__const._Z4testj.digits,@object # @__const._Z4testj.digits
.section .rodata.str1.1,"aMS",@progbits,1
.L__const._Z4testj.digits:
.asciz "foobar"
.size .L__const._Z4testj.digits, 7

.ident "clang version 24.0.0git"
.section ".note.GNU-stack","",@progbits
.addrsig
```
Running it through LLD:
```
llvm-mc --triple=s390x-unknown-linux-gnu test.s -filetype=obj > test.o
ld.lld -m elf64_s390 -pie -o a.out test.o
```
Results in an assertion failure:
```
ld.lld: /home/npopov/repos/llvm-project/lld/ELF/Writer.cpp:2166: void (anonymous namespace)::Writer>::finalizeSections() [ELFT = llvm::object::ELFType]: Assertion `llvm::none_of(ctx.removedSyntheticSections, [](SyntheticSection *sec) { return sec->isNeeded(); })' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and instructions to reproduce the bug.
Stack dump:
0. Program arguments: build/bin/ld.lld -m elf64_s390 -pie -o a.out test.o
#0 0x00000000056fbbfb llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (build/bin/ld.lld+0x56fbbfb)
#1 0x00000000056f8971 llvm::sys::RunSignalHandlers() (build/bin/ld.lld+0x56f8971)
#2 0x00000000056fc63b SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
#3 0x00007fc034620fb0 __restore_rt (/lib64/libc.so.6+0x19fb0)
#4 0x00007fc03467bccc __pthread_kill_implementation (/lib64/libc.so.6+0x74ccc)
#5 0x00007fc034620e8e gsignal (/lib64/libc.so.6+0x19e8e)
#6 0x00007fc0346087b3 abort (/lib64/libc.so.6+0x17b3)
#7 0x00007fc034609804 _IO_peekc_locked.cold (/lib64/libc.so.6+0x2804)
#8 0x00007fc034618d45 __assert_fail (/lib64/libc.so.6+0x11d45)
#9 0x0000000005a906f6 (anonymous namespace)::Writer>::finalizeSections() Writer.cpp:0:0
#10 0x0000000005a61bd5 void lld::elf::writeResult>(lld::elf::Ctx&) (build/bin/ld.lld+0x5a61bd5)
```

Start with lld/ELF/Writer.cpp, especially finalizeSections() near the assertion in the stack trace. Reproduce the failure by assembling test.s with llvm-mc for s390x and linking test.o with ld.lld -m elf64_s390 -pie. Done when this input no longer triggers the assertion and the behavior is covered by an appropriate test.

Written by the indexing model from the issue text.