revert: [ELF] - Versionscript: support mangled symbols with the same name.

Something broked BBots:
281318 failed on step 9:
http://lab.llvm.org:8011/builders/clang-with-lto-ubuntu/builds/413

r281317 built step 9 green:
http://lab.llvm.org:8011/builders/clang-with-lto-ubuntu/builds/415

Initial revision commits were:
This is PR30312. Info from bug page:

Both of these symbols demangle to abc::abc():
_ZN3abcC1Ev
_ZN3abcC2Ev
(These would be abc's complete object constructor and base object constructor, respectively.)
however with "abc::abc()" in the version script only one of the two receives the symbol version.

Patch fixes that.
It uses testcase created by Ed Maste (D24306).

Differential revision: https://reviews.llvm.org/D24336

llvm-svn: 281411