Testsuite fixes for hppa64-hpux

Testsuite fixes for hppa64-hpux

HPUX has a different .comm syntax, and anything in the first column
is a label.

gas/
	* testsuite/gas/elf/strtab.s: Don't put directives on first
	column or continuation with labels not in first column.
ld/
	* testsuite/ld-elf/elf.exp: Xfail pr20995 tests on hppa64-hpux.
	Set up HPUX defsym.  Run pr14170 tests and build symbol3 objects,
	defining HPUX where necessary.  Define HPUX for implib tests.
	* testsuite/ld-elf/comm-data4.d: Run for hpux.
	* testsuite/ld-elf/endsym.d: Likewise.
	* testsuite/ld-elf/linkoncerdiff.d: Likewise.
	* testsuite/ld-elf/comm-data4.s: Add alternate .comm when HPUX.
	* testsuite/ld-elf/comm-data5.s: Likewise.
	* testsuite/ld-elf/endsym.s: Likewise.
	* testsuite/ld-elf/pr14170c.s: Likewise.
	* testsuite/ld-elf/symbol3.s: Likewise.
	* testsuite/ld-elf/implib.s: Likewise.  Don't start directives
	in first column.
	* testsuite/ld-elf/linkoncerdiff2.s: Don't use numeric labels.
	* testsuite/ld-elf/warn3.d: Run for hpux.
	* testsuite/ld-scripts/rgn-at10.d: Xfail for hpux.
	* testsuite/ld-scripts/rgn-at11.d: Likewise.
	* testsuite/ld-scripts/size-2.d: Remove xfail for hpux.