[llvm-objdump] - Change the output for --all-headers.

This is for https://bugs.llvm.org/show_bug.cgi?id=40008,

it starts printing the file headers when --all-headers is given and
do a minor cosmetic change.

Differential revision: https://reviews.llvm.org/D56588

llvm-svn: 351006
diff --git a/llvm/test/tools/llvm-objdump/all-headers.test b/llvm/test/tools/llvm-objdump/all-headers.test
new file mode 100644
index 0000000..6bb9a84
--- /dev/null
+++ b/llvm/test/tools/llvm-objdump/all-headers.test
@@ -0,0 +1,20 @@
+# RUN: yaml2obj %s > %t
+# RUN: llvm-objdump --all-headers %t | FileCheck %s
+
+## Check we print file format, architecture and start address before
+## anything else when using --all-headers.
+
+# CHECK:       file format ELF64-x86-64
+# CHECK-EMPTY:
+# CHECK-NEXT:  architecture: x86_64
+# CHECK-NEXT:  start address: 0x0000000000000000
+# CHECK-EMPTY:
+# CHECK-NEXT:  Sections:
+
+!ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_EXEC
+  Machine:         EM_X86_64
+Sections: