[yaml2obj][test] - Ensure that dynamic section has sh_entsize correctly set.

[grimar]

Summary

This updates the existent test because it lacks coverage.

[jhenderson]

LGTM for this change, although it looks like this test should have quite a bit more to it for testing the dynamic section.

llvm/test/tools/yaml2obj/ELF/dynamic-section.yaml

 ## Ensures that dynamic section has sh_entsize correctly set.
 
-# RUN: yaml2obj %s -o %t
-# RUN: llvm-readobj --sections %t | FileCheck %s --check-prefix=SECTION
+# RUN: yaml2obj -DBITS=64 %s -o %t.64
+# RUN: llvm-readobj --sections %t.64 | FileCheck %s -DENTSIZE=16
+# RUN: yaml2obj -DBITS=32 %s -o %t.32
+# RUN: llvm-readobj --sections %t.32 | FileCheck %s -DENTSIZE=8
 
 !ELF
 FileHeader:
-  Class:           ELFCLASS64
-  Data:            ELFDATA2LSB
-  Type:            ET_DYN
-  Machine:         EM_X86_64
+  Class:   ELFCLASS[[BITS]]
+  Data:    ELFDATA2LSB
+  Type:    ET_DYN
+  Machine: EM_X86_64
 Sections:
-  - Name: .dynamic
-    Type: SHT_DYNAMIC
+## Test default values set by yaml2obj.
+  - Name:  .dynamic
+    Type:  SHT_DYNAMIC
     Flags: [ SHF_ALLOC, SHF_WRITE ]
+## Test we can use an arbitrary value for sh_entsize.
+  - Name:    .mydynamic
+    Type:    SHT_DYNAMIC
+    EntSize: 0xFE
 
-# SECTION: Name: .dynamic
-# SECTION: EntrySize: 16
+# CHECK:      Name:      .dynamic
+# CHECK:      EntrySize:
+# CHECK-SAME:           {{^}} [[ENTSIZE]]{{$}}
+# CHECK:      Name:      .mydynamic
+# CHECK:      EntrySize:
+# CHECK-SAME:           {{^}} 254{{$}}