Convert indirect calls to direct when possible.

Convert indirect calls to direct when possible.

Please see patch discussion:
https://www.sourceware.org/ml/binutils/2016-05/msg00322.html

2016-06-28  Sriraman Tallam  <tmsriram@google.com>

	* x86_64.cc (Lazy_view): New class.
	(can_convert_mov_to_lea): Templatize function.  Make the function
	check for appropriate relocation types and use the view parameter
	to get section contents.
	(can_convert_callq_to_direct): New function.
	(Target_x86_64<size>::Scan::global): Refactor.
	(Target_x86_64<size>::Relocate::relocate): Refactor. Change any indirect
	call via GOT that can be converted.
	* testsuite/Makefile.am (x86_64_indirect_call_to_direct.sh): New test.
	* testsuite/Makefile.in: Regenerate.
	* testsuite/x86_64_indirect_call_to_direct1.s: New file.
	* testsuite/x86_64_indirect_jump_to_direct1.s: New file.