cxxfilt test failures
Fixes these:
bfin-elf +FAIL: cxxfilt: demangling _Z1fIvJiELb0EEvPDOT1_EFT_DpT0_E
bfin-elf +FAIL: cxxfilt: demangling _Z14int_if_addableI1YERiP1AIXszpldecvPT_Li0EdecvS4_Li0EEE
h8300-elf +FAIL: cxxfilt: demangling _Z1fIvJiELb0EEvPDOT1_EFT_DpT0_E
h8300-elf +FAIL: cxxfilt: demangling _Z14int_if_addableI1YERiP1AIXszpldecvPT_Li0EdecvS4_Li0EEE
i686-pe +FAIL: cxxfilt: demangling _Z1fIvJiELb0EEvPDOT1_EFT_DpT0_E
i686-pe +FAIL: cxxfilt: demangling _Z14int_if_addableI1YERiP1AIXszpldecvPT_Li0EdecvS4_Li0EEE
i686-vxworks +FAIL: cxxfilt: demangling _Z1fIvJiELb0EEvPDOT1_EFT_DpT0_E
i686-vxworks +FAIL: cxxfilt: demangling _Z14int_if_addableI1YERiP1AIXszpldecvPT_Li0EdecvS4_Li0EEE
m32c-elf +FAIL: cxxfilt: demangling _Z1fIvJiELb0EEvPDOT1_EFT_DpT0_E
m32c-elf +FAIL: cxxfilt: demangling _Z14int_if_addableI1YERiP1AIXszpldecvPT_Li0EdecvS4_Li0EEE
* testsuite/binutils-all/cxxfilt.exp: Pass --no-strip-underscores
unconditionally to tests needing the option rather than via a
list of targets.