glsl: fix use-after free bug/crash in ast_declarator_list::hir()
The call to get_variable_being_redeclared() may delete 'var' so we
can't reference var->name afterward. We fix that by examining the
var's name before making that call.
Fixes valgrind warnings and possible crash when running the piglit
tests/spec/glsl-1.30/execution/clipping/vs-clip-distance-in-param.shader_test
test (and probably others).
Cc: "10.1 10.2" <mesa-stable@lists.freedesktop.org>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>