[AArch64] Fix off by one error in instruction relaxation mask.

The AArch64 TLSDESC to IE relaxation code uses a bit mask intended to
ensure that destination register in a relaxed ldr instruction is
always X0.  The mask has an off by one error resulting in the most
significant bit of the destination register being retained in the
relaxed instruction.  The issue generally appears when the compiler
emits TLS accesses code under high register pressure resulting in a
broken code sequence.
Test suite cleanup.

2014-04-15  Keith Seitz  <keiths@redhat.com>

	* gdb.mi/mi-break.exp (test_tbreak_creation_and_listing): Remove
	unused globals.
	(test_rbreak_creation_and_listing): Likewise.
	(test_ignore_count): Likewise.
	(test_error): Likewise.
Allow target to derive from Copy_relocs class.

2014-04-15  Sasa Stankovic  <Sasa.Stankovic@imgtec.com>

gold/
	* copy-relocs.cc (Copy_relocs::Copy_reloc_entry::emit): Remove and
	inline into ...
	(Copy_relocs::emit): ... here.
	* copy-relocs.h (Copy_reloc_entry): Change from class to struct.
	(Copy_reloc_entry::make_copy_reloc): Change from private to protected.
	(Copy_reloc_entry::entries_): Change from private to protected.
Allow target to decide whether to include a section.

2014-04-15  Sasa Stankovic  <Sasa.Stankovic@imgtec.com>

gold/
	* layout.cc (Layout::include_section): Allow a target to decide
	whether to include a section.
	* target.h (Target::should_include_section): New function.
	(Target::do_should_include_section): New function.