[ELF][Reader] Remove static ordinal.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@177561 91177308-0d34-0410-b5e6-96231b3b80d8
[ELF][Reader] Refactor how relocations are read. Improves performance.

This changes from reading each relocation individually for each section to just
storing the range of relocations. It also counts the relocations to preallocate
the _references array.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@177562 91177308-0d34-0410-b5e6-96231b3b80d8
[ELF][Reader][Perf] Only do loookup once.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@177563 91177308-0d34-0410-b5e6-96231b3b80d8
[ELF][Reader] Add debug message to print all inputs the linker actually read.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@177564 91177308-0d34-0410-b5e6-96231b3b80d8