Regressions on trunk at revision 229831 vs revision 229825

[H.J. Lu Intel64 Core i7]

New failures:
FAIL: compiler driver --help=c++ option(s): "^ +-.*[^:.]$" absent from output: "  -Wplacement-new             Warn for placement new expressions with undefined behavior"
FAIL: compiler driver --help=c++ option(s): "^ +-.*[^:.]$" absent from output: "  -Wplacement-new             Warn for placement new expressions with undefined behavior"
FAIL: compiler driver --help=warnings option(s): "^ +-.*[^:.]$" absent from output: "  -Wplacement-new             Warn for placement new expressions with undefined behavior"
FAIL: compiler driver --help=warnings option(s): "^ +-.*[^:.]$" absent from output: "  -Wplacement-new             Warn for placement new expressions with undefined behavior"
FAIL: g++.dg/warn/Wplacement-new-size.C  -std=gnu++11 (test for excess errors)
FAIL: g++.dg/warn/Wplacement-new-size.C  -std=gnu++14 (test for excess errors)
FAIL: g++.dg/warn/Wplacement-new-size.C  -std=gnu++98 (test for excess errors)

New passes: