[test] Change llvm-readobj -long-option to --long-option or well-known short options. NFC

Also change some options that have different semantics (cause confusion) in llvm-readelf mode:

-s => -S
-t => --symbols
-sd => --section-data

llvm-svn: 359651
diff --git a/lld/test/ELF/tls-dynamic.s b/lld/test/ELF/tls-dynamic.s
index a416706..d7c2e1f 100644
--- a/lld/test/ELF/tls-dynamic.s
+++ b/lld/test/ELF/tls-dynamic.s
@@ -1,7 +1,7 @@
 // REQUIRES: x86
 // RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
 // RUN: ld.lld --hash-style=sysv -shared %t -o %tout
-// RUN: llvm-readobj -sections -relocations %tout | FileCheck %s
+// RUN: llvm-readobj --sections -r %tout | FileCheck %s
 // RUN: llvm-objdump -d %tout | FileCheck %s --check-prefix=DIS
 
   leaq  a@tlsld(%rip), %rdi