Remove code for AIX, Sun, HP-UX and more

[bernardnormier]

We want to remove this code as it's confusing to keep unused conditionals.

% rg -i hpux -g \*.{cpp\,h}
cpp/src/Slice/Grammar.cpp
379:#ifdef __hpux

cpp/src/IceStorm/Grammar.cpp
214:#ifdef __hpux

cpp/src/Ice/DynamicLibrary.cpp
134:#elif defined(__hpux)

cpp/src/IceGrid/Grammar.cpp
248:#ifdef __hpux

cpp/src/Ice/Network.cpp
9:#if defined(__hpux)
501:#elif !defined(__hpux)

cpp/src/Ice/Network.h
8:#ifdef __hpux

cpp/test/Ice/stringConverter/Client.cpp

% rg -i _aix -g \*.{cpp\,h}
cpp/src/Glacier2CryptPermissionsVerifier/CryptPermissionsVerifierI.cpp
14:#if defined(__GLIBC__) || defined(_AIX)

cpp/src/IceStorm/Grammar.cpp
360:#            elif defined _AIX

cpp/src/IceGrid/Activator.cpp
38:#if defined(__linux__) || defined(__sun) || defined(_AIX) || defined(__GLIBC__)
657:#    ifdef _AIX

cpp/src/IceGrid/Grammar.cpp
394:#            elif defined _AIX

cpp/test/IceSSL/configuration/AllTests.cpp
2454:#if !defined(_AIX)

cpp/src/Ice/DynamicLibrary.cpp
144:#elif defined(_AIX)
199:#    ifdef _AIX

cpp/test/Ice/stringConverter/Client.cpp
57:#elif defined(_AIX) && !defined(_LIBICONV_VERSION)

cpp/src/Ice/Instance.cpp
71:#if defined(__linux__) || defined(__sun) || defined(_AIX) || defined(__GLIBC__)

cpp/src/Ice/Network.cpp
263:#    ifdef _AIX
530:#        ifdef _AIX

cpp/src/Slice/Grammar.cpp
525:#            elif defined _AIX

cpp/src/Ice/Exception.cpp
53:#    if !defined(_AIX) && !defined(__FreeBSD__) && !defined(ICE_STATIC_LIBS)

cpp/test/IceGrid/replicaGroup/RegistryPlugin.cpp
52:#ifndef _AIX

java/src/IceGridGUI/src/main/java/com/zeroc/IceGridGUI/Logger.java
21:    // Ignore spurious selector wake up warnings in solaris.
23:    if (OS_IS_SOLARIS && message.equals("spurious selector wake up")) {
44:  private static final boolean OS_IS_SOLARIS = System.getProperty("os.name").equals("SunOS");

cpp/src/Ice/SSL/OpenSSLTransceiverI.cpp
255:        // The const_cast is necessary because Solaris still uses OpenSSL 0.9.7.

cpp/src/Ice/Network.cpp
316:                    // On Solaris the above Loopback check does not always work so we double
317:                    // check the address below. Solaris also returns duplicate entries that need