Refresh android relocation packer from AOSP bionic.

Refresh android relocation packer from AOSP bionic.

Refresh android relocation packer from AOSP bionic.

Imports:
  Fix unit tests, and extend for other architectures
    https://android-review.googlesource.com/#/c/151901/

  Do not adjust PT_GNU_STACK segment
    https://android-review.googlesource.com/#/c/149300/

  Adjust DT_MIPS_RLD_MAP2 value
    https://android-review.googlesource.com/#/c/148822/

  Reduce p_align for program header to page size.
    https://android-review.googlesource.com/#/c/148492/

  Exit normally when relocations are already packed.
    https://android-review.googlesource.com/#/c/148175/

Un-revert of: https://codereview.chromium.org/1143303007/
Original: https://codereview.chromium.org/1164453002/

TBR=rmcilroy@chromium.org
BUG=385553

Review URL: https://codereview.chromium.org/1161873011

Cr-Commit-Position: refs/heads/master@{#331964}