Object file support for s390x (#2872)

Add support for s390x binary format object files.  In particular,
add support for s390x ELF relocation types (currently only
S390xPCRel32Dbl).

crates/profiling/src/jitdump_linux.rs

@@ -241,6 +241,7 @@ impl State {
             Architecture::X86_32(_) => elf::EM_386 as u32,
             Architecture::Arm(_) => elf::EM_ARM as u32,
             Architecture::Aarch64(_) => elf::EM_AARCH64 as u32,
+            Architecture::S390x => elf::EM_S390 as u32,
             _ => unimplemented!("unrecognized architecture"),
         }
     }