remove unused Half type

include/avian/codegen/ir.h

@@ -35,11 +35,6 @@ class Type {
     Float,
     Address,
 
-    // Represents individual halves of two-word types
-    // (double/long on 32-bit systems)
-    // TODO: remove when possible
-    Half,
-
     // Represents the lack of a return value
     // TODO: remove when possible
     Void,

src/codegen/compiler.cpp

@@ -1309,7 +1309,6 @@ unsigned typeFootprint(Context* c, ir::Type type)
     return type.rawSize() / 4;
   case ir::Type::Object:
   case ir::Type::Address:
-  case ir::Type::Half:
     return 1;
   case ir::Type::Void:
     return 0;