[debuginfo-tests] Update test for double-dash long-option.

Author: JDevlieghere

debuginfo-tests/llgdb-tests/apple-accel.cpp

@@ -4,9 +4,9 @@
 // These sections are going to be retired in DWARF 5, so we hardcode
 // the DWARF version in the tests.
 // RUN: %clang %s %target_itanium_abi_host_triple -gdwarf-2 -O0 -c -g -o %t-ex
-// RUN: llvm-objdump -section-headers %t-ex | FileCheck %s
+// RUN: llvm-objdump --section-headers %t-ex | FileCheck %s
 // RUN: %clang %s %target_itanium_abi_host_triple -gdwarf-4 -O0 -c -g -o %t-ex
-// RUN: llvm-objdump -section-headers %t-ex | FileCheck %s
+// RUN: llvm-objdump --section-headers %t-ex | FileCheck %s
 
 // A function in a different section forces the compiler to create the
 // __debug_ranges section.