MIPS/LD/testsuite: Adjust match patterns for special section indexes

MIPS/LD/testsuite: Adjust match patterns for special section indexes

Update `readelf' symbol table dump match patterns to handle SHN_MIPS_DATA
and SHN_MIPS_TEXT special section indexes produced by the IRIX ELF format
variation used with a number of MIPS targets and printed by `readelf' as
PRC[0xff02] and PRC[0xff01] respectively, correcting LD test suite
failures:

extra regexps in .../ld/testsuite/ld-elf/comm-data1.sd starting with "^ +[0-9]+: +[0-9a-f]+ +0 +OBJECT +GLOBAL +DEFAULT +[0-9]+ +foo$"
EOF from dump.out
FAIL: Common symbol override test (auxiliary shared object build)

extra regexps in .../ld/testsuite/ld-elf/pr21703-shared.sd starting with "^ +[0-9]+: +[0-9a-f]+ +4 +FUNC +GLOBAL +DEFAULT +[0-9] +foo@FOO$"
EOF from dump.out
FAIL: PR ld/21703 shared

extra regexps in .../ld/testsuite/ld-elf/comm-data1.sd starting with "^ +[0-9]+: +[0-9a-f]+ +0 +OBJECT +GLOBAL +DEFAULT +[0-9]+ +foo$"
EOF from dump.out
FAIL: MIPS o32/copyreloc common symbol override test (auxiliary shared object build)

extra regexps in .../ld/testsuite/ld-elf/comm-data1.sd starting with "^ +[0-9]+: +[0-9a-f]+ +0 +OBJECT +GLOBAL +DEFAULT +[0-9]+ +foo$"
EOF from dump.out
FAIL: MIPS o32/nocopyreloc common symbol override test (auxiliary shared object build)

observed due to file contents like:

     7: 5ffe02e8     0 OBJECT  GLOBAL DEFAULT PRC[0xff02] foo

shown by `readelf -s' vs:

 +[0-9]+: +[0-9a-f]+ +0 +OBJECT +GLOBAL +DEFAULT +[0-9]+ +foo

pattern expected, triggered by widening testing to these targets by commit
05a5feafdd38 ("Rewrite check_shared_lib_support").

	ld/
	* testsuite/ld-elf/comm-data1.sd: Alternatively accept
	`PRC[0xff02]' in place of a regular section index.
	* testsuite/ld-elf/pr21703-shared.sd: Likewise `PRC[0xff01]'.