elf: Add PT_GNU_PROPERTY segment type

elf: Add PT_GNU_PROPERTY segment type

Linkers group input note sections with the same name into one output
note section with the same name.  One output note section is placed in
one PT_NOTE segment.  New linkers merge all input .note.gnu.property
sections into one output .note.gnu.property section with a single
NT_GNU_PROPERTY_TYPE_0 note in a single PT_NOTE segment.  Since older
linkers treat input .note.gnu.property section as a generic note section
and just concatenate all input .note.gnu.property sections into one
output .note.gnu.property section without merging them, we may
see one or more NT_GNU_PROPERTY_TYPE_0 notes in PT_NOTE segment, which
are invalid.

GNU_PROPERTY_X86_UINT32_VALID was defined to address this issue such
that linker sets the bit for non-relocatable outputs.  But it isn't
sufficient:

1. It doesn't cover generic properties.
2. When -mx86-used-note=yes is passed to x86 assembler, the
GNU_PROPERTY_X86_UINT32_VALID bit is set in GNU_PROPERTY_X86_ISA_1_USED
property in object file and older linkers generate invalid
NT_GNU_PROPERTY_TYPE_0 notes with the GNU_PROPERTY_X86_UINT32_VALID bit
set.

I am proposing the following changes:

1. Add PT_GNU_PROPERTY segment type:

 # define PT_GNU_PROPERTY (PT_LOOS + 0x474e553)

which covers .note.gnu.property section.
2. Remove GNU_PROPERTY_X86_UINT32_VALID.

bfd/

	PR ld/23900
	* elf.c (get_program_header_size): Add a PT_GNU_PROPERTY
	segment for NOTE_GNU_PROPERTY_SECTION_NAME.
	(_bfd_elf_map_sections_to_segments): Create a PT_GNU_PROPERTY
	segment for NOTE_GNU_PROPERTY_SECTION_NAME.
	* elfxx-x86.c (_bfd_elf_link_setup_gnu_properties): Don't set
	GNU_PROPERTY_X86_UINT32_VALID.

binutils/

	PR ld/23900
	* readelf.c (get_segment_type): Support PT_GNU_PROPERTY.
	(decode_x86_isa): Don't check GNU_PROPERTY_X86_UINT32_VALID.
	(decode_x86_feature_1): Likewise.
	(decode_x86_feature_2): Likewise.
	(print_gnu_property_note): Remove GNU_PROPERTY_X86_UINT32_VALID
	check.
	* testsuite/binutils-all/i386/empty.d: Updated.
	* testsuite/binutils-all/x86-64/empty-x32.d: Likewise.
	* testsuite/binutils-all/x86-64/empty.d: Likewise.
	* testsuite/binutils-all/i386/pr21231b.s: Change
	GNU_PROPERTY_X86_ISA_1_USED bits to 0x7fffffff.
	* testsuite/binutils-all/x86-64/pr21231b.s: Likewise.

gas/

	PR ld/23900
	* config/tc-i386.c (x86_cleanup): Don't set
	GNU_PROPERTY_X86_UINT32_VALID.
	* testsuite/gas/i386/property-1.s: Change
	GNU_PROPERTY_X86_ISA_1_USED bits to 0.

include/

	PR ld/23900
	* elf/common.h (PT_GNU_PROPERTY): New.
	(GNU_PROPERTY_X86_UINT32_VALID): Removed.

ld/

	PR ld/23900
	* testsuite/ld-elf/elf.exp: Run PR ld/23900 test.
	* testsuite/ld-elf/pr23900-1-32.rd: New file.
	* testsuite/ld-elf/pr23900-1-64.rd: Likewise.
	* testsuite/ld-elf/pr23900-1.d: Likewise.
	* testsuite/ld-elf/pr23900-1.s: Likewise.
	* testsuite/ld-elf/pr23900-2.s: Likewise.
	* testsuite/ld-elf/pr23900-2a.d: Likewise.
	* testsuite/ld-elf/pr23900-2b.d: Likewise.
	* testsuite/ld-i386/ibt-plt-1.d: Adjusted.
	* testsuite/ld-i386/ibt-plt-2c.d: Likewise.
	* testsuite/ld-i386/ibt-plt-2d.d: Likewise.
	* testsuite/ld-i386/ibt-plt-3d.d: Likewise.
	* testsuite/ld-x86-64/ibt-plt-1-x32.d: Likewise.
	* testsuite/ld-x86-64/ibt-plt-1.d: Likewise.
	* testsuite/ld-x86-64/ibt-plt-2c-x32.d: Likewise.
	* testsuite/ld-x86-64/ibt-plt-2c.d: Likewise.
	* testsuite/ld-x86-64/ibt-plt-2d-x32.d: Likewise.
	* testsuite/ld-x86-64/ibt-plt-2c.d: Likewise.
	* testsuite/ld-x86-64/ibt-plt-3c-x32.d: Likewise.
	* testsuite/ld-x86-64/ibt-plt-3c.d: Likewise.
	* testsuite/ld-x86-64/ibt-plt-3d-x32.d: Likewise.
	* testsuite/ld-x86-64/ibt-plt-3d.d: Likewise.
	* testsuite/ld-i386/pr23372c.d: Expect <None>
	for GNU_PROPERTY_X86_ISA_1_USED.
	* testsuite/ld-x86-64/pr23372c-x32.d: Likewise.
	* testsuite/ld-x86-64/pr23372c.d: Likewise.
	* testsuite/ld-x86-64/pr23372d-x32.d: Likewise.
	* testsuite/ld-x86-64/pr23372d.d: Likewise.
	* testsuite/ld-x86-64/property-x86-5a.s: Change
	GNU_PROPERTY_X86_ISA_1_USED bits to 0.
	* testsuite/ld-x86-64/property-x86-5b.s: Likewise.