More hacking on --with-locales

Propagate the restriction of locales into <config_locales.h>. Note that in the
normal case, with no locale restrictions, all the WITH_LOCALE_xx macros are
zero anyway, but WITH_LOCALE_ALL is one.

Restrict which character encodings are handled in
sal/textencsal/textenc/tables.cxx based on the WITH_LOCALE_ macros. (Don't
simply always do it for iOS.)

Massage the affected unit tests to not crash when only partial character
encoding information is present.

Change-Id: Ie2c882c262ebd0d2b37dde66b8fe3c3e2570da14
Sprinkle SAL_OVERRIDE

Change-Id: Ifad2710470fc41257f616d716eb9323094a69de1
WaE: overriding virtual function declaration not marked 'override'

Change-Id: I1a7172cb9b2663b84874b3c3f277fb3b3786c7a4