testsuite: Also discard the `.MIPS.options' section

Also discard the `.MIPS.options' section, used with n64 MIPS binaries,
along with similar other MIPS sections (`.reginfo', `.MIPS.abiflags')
not relevant for the test cases concerned, fixing these regressions:

mips64-openbsd  -FAIL: ld-elf/group3a
mips64-openbsd  -FAIL: ld-elf/group3b
mips64-openbsd  -FAIL: Place orphan sections (map file check)
mips64-openbsd  -FAIL: ld-elf/orphan-region
mips64-openbsd  -FAIL: ld-elf/orphan
mips64-openbsd  -FAIL: overlay size (map file check)
mips64-openbsd  -FAIL: overlay size
mips64el-openbsd  -FAIL: ld-elf/group3a
mips64el-openbsd  -FAIL: ld-elf/group3b
mips64el-openbsd  -FAIL: Place orphan sections (map file check)
mips64el-openbsd  -FAIL: ld-elf/orphan-region
mips64el-openbsd  -FAIL: ld-elf/orphan
mips64el-openbsd  -FAIL: overlay size (map file check)
mips64el-openbsd  -FAIL: overlay size

Co-Authored-By: Maciej W. Rozycki <macro@orcam.me.uk>

	binutils/
	* testsuite/binutils-all/strip-3.d: Add `-R .MIPS.options' to
	the `strip' tag.

	ld/
	* testsuite/ld-elf/group.ld: Also discard `.MIPS.options'.
	* testsuite/ld-elf/orphan-region.ld: Likewise.
	* testsuite/ld-elf/orphan.ld: Likewise.
	* testsuite/ld-mips-elf/got-page-1.ld: Likewise.
	* testsuite/ld-scripts/overlay-size.t: Likewise.