x86: Change PLT32 reloc against section to PC32

Commit 292676c1 resolved PLT32 reloc aganst local symbol to section.
Since PLT32 relocation must be against symbols, turn such PLT32
relocation into PC32 relocation.

gas/

	PR gas/26263
	* config/tc-i386.c (i386_validate_fix): Change PLT32 reloc
	against section to PC32 reloc.
	* testsuite/gas/i386/relax-5.d: Updated.
	* testsuite/gas/i386/x86-64-relax-4.d: Likewise.

ld/

	PR gas/26263
	* testsuite/ld-i386/i386.exp: Run PR gas/26263 test.
	* testsuite/ld-x86-64/x86-64.exp: Likewise.
	* testsuite/ld-i386/pr26263.d: New file.
	* testsuite/ld-x86-64/pr26263.d: Likewise.
	* testsuite/ld-x86-64/pr26263.s: Likewise.

(cherry picked from commit 2585b7a5)