so that --noinhibit-exec downgrades the error to a warning, which helps
debugging when `PHDRS` is specified without `PT_TLS`. Also update the
message to make it accurate: STT_TLS may exist in the absence of PT_TLS.
In addition, invoking `exitLld(1)` (through `fatal`) is problematic
(#66974): When a thread is `exitLld(1)`, triggering `llvm_shutdown`,
another thread may be at `relocateAlloc`, accessing `sec.relocs()` which
got destroyed(tampered?), leading to
incorrect `llvm_unreachable("invalid expression")`.
b6448a03d8