[ELF] - Added testcase relative to D25090.

It was requested on review for https://reviews.llvm.org/D25090 to add testcase in lld.

Spec says (http://www.sco.com/developers/gabi/1998-04-29/ch4.eheader.html) :
e_shnum
This member holds the number of entries in the section header table. 
Thus the product of e_shentsize and e_shnum gives the section header table's size in bytes.
If a file has no section header table, e_shnum holds the value zero.

In case revealed, broken input did not contain zero in this field.
 LLD then could crash when proccessed sections (returned array has incorrect size):

template <class ELFT> void SharedFile<ELFT>::parseSoName() {
...
  for (const Elf_Shdr &Sec : Obj.sections()) {
...

llvm-svn: 284375