Fix relocation to look for symbols in local group

  The local group is a sequence of libraries in default (breadth-first)
  order. It allows RTLD_LOCALLY loaded library to correctly relocate
  symbols within its group (see test-cases).

  Local group lookup is performed after main executable and ld_preloads.

Bug: 2643900
Bug: 15432753
Bug: 18186310

(cherry picked from commit cfa97f17)

Change-Id: I5fa8c673f929e4652c738912c7ae078d7ec286d2