[RuntimeDyld] Make RuntimeDyld honor the ProcessAllSections flag.

[RuntimeDyld] Make RuntimeDyld honor the ProcessAllSections flag.

When the ProcessAllSections flag (introduced in r204398) is set RuntimeDyld is
supposed to make a call to the client's memory manager for every section in each
object that is loaded. Due to some missing checks, this was not happening in all
cases. This patch adds the missing cases, and fixes the Orc unit test that
verifies correct behavior for ProcessAllSections (The unit test had been
silently bailing out due to an ordering issue: a change in the test order meant
that this unit-test was running before the native target was registered. This
issue has also been fixed in this patch).

This fixes <rdar://problem/22789965>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@299449 91177308-0d34-0410-b5e6-96231b3b80d8