MC: Evaluate .org during fragment relaxation

Similar to 742ecfc13e8aa34cfff2900e31838f657fcafe30 for MCFillFragment,
ensure `.org` directives with expressions are re-evaluated during
fragment relaxation, as their sizes may change. Continue iteration to
prevent stale, incorrect sizes. While I knew MCOrgFragment likely needed
to be re-evaluated at all, I did not have a motivation to add it;-)

This fixes the root cause of
https://github.com/ClangBuiltLinux/linux/issues/2116
(writeSectionData assertion failure when building the Linux kernel for arm64)

The issue cannot be reliably replicated. The specific test case would
not replicate if any of the following condition was not satisfied:

* .org was not re-evaluated. Fixed by this commit.
* clang -cc1as has a redundant `initSections` call, leading to a
  redundant initial FT_Align fragment. llvm-mc -filetype=obj, lacking
  the redundant `initSections`, doesn't replicate.
* faa931b717c02d57f0814caa9133219040e6a85b decreased sizeof(MCFragment).
* f1aa6050bd90f8ec4273da55d362e23905ad3a81 added more fragments

0 files changed, 0 insertions, 0 deletions