PR libstdc++/81092 add std::wstring symbols and bump library version

	PR libstdc++/81092
	* acinclude.m4: Bump libtool_VERSION.
	* config/abi/post/i386-linux-gnu/baseline_symbols.txt: Update.
	* config/abi/post/x86_64-linux-gnu/32/baseline_symbols.txt: Update.
	* config/abi/pre/gnu.ver: Add wstring constructor symbols to
	GLIBCXX_3.4.24 version and move random_device::_M_get_entropy() symbol
	to new GLIBCXX_3.4.25 version.
	* doc/xml/manual/abi.xml: Document new versions.
	* doc/html/*: Regenerate.
	* testsuite/21_strings/basic_string/cons/char/8.cc: Use base object
	constructors to ensure required symbols are exported.
	* testsuite/21_strings/basic_string/cons/wchar_t/8.cc: Likewise.
	* testsuite/util/testsuite_abi.cc: Add new version.

From-SVN: r249246