tbv2: use std::decay_t in make_field

CodeGen v2 permits template parameters to be qualified. This means that if we
call `make_field` with a template parameter it will be qualified. However, we
don't qualify the types when generating meta functions such as `NameProvider`
and `TypeHandler`. This means these qualified types don't match up with the
expected type.

Use `std::decay_t` when forwarding the type to `NameProvider` and `TypeHandler`
so they're always the base type that they were generated with.

Test Plan:
- CI
- Added a test for `std::unique_ptr<const Foo>` to exercise this. Failed
  before, passes after.

oi/CodeGen.cpp

@@ -1072,9 +1072,9 @@ constexpr inst::Field make_field(std::string_view name) {
     sizeof(T),
     ExclusiveSizeProvider<T>::size,
     name,
-    NameProvider<T>::names,
-    TypeHandler<Ctx, T>::fields,
-    TypeHandler<Ctx, T>::processors,
+    NameProvider<std::decay_t<T>>::names,
+    TypeHandler<Ctx, std::decay_t<T>>::fields,
+    TypeHandler<Ctx, std::decay_t<T>>::processors,
   };
 }
 )";

test/integration/std_smart_ptr.toml

@@ -31,6 +31,31 @@ definitions = '''
       }
     ]
     '''
+  [cases.unique_ptr_const_uint64_empty]
+    param_types = ["std::unique_ptr<const std::uint64_t>&"]
+    setup = "return {nullptr};"
+    expect_json = '''
+    [
+      {
+        "staticSize": 8,
+        "dynamicSize": 0,
+        "exclusiveSize": 8,
+        "length": 0,
+        "capacity": 1,
+        "elementStaticSize": 8
+      }
+    ]
+    '''
+    expect_json_v2 = '''
+    [
+      {
+        "staticSize": 8,
+        "exclusiveSize": 8,
+        "length": 0,
+        "capacity": 1
+      }
+    ]
+    '''
   [cases.unique_ptr_uint64_present]
     param_types = ["std::unique_ptr<std::uint64_t>&"]
     setup = "return {std::make_unique<std::uint64_t>(64)};"
@@ -181,6 +206,30 @@ definitions = '''
       }
     ]
     '''
+  [cases.shared_ptr_const_uint64_empty]
+    param_types = ["std::shared_ptr<const std::uint64_t>&"]
+    setup = "return {nullptr};"
+    expect_json = '''
+    [
+      {
+        "staticSize": 16,
+        "dynamicSize": 0,
+        "length": 0,
+        "capacity": 1,
+        "elementStaticSize": 8
+      }
+    ]
+    '''
+    expect_json_v2 = '''
+    [
+      {
+        "staticSize": 16,
+        "exclusiveSize": 16,
+        "length": 0,
+        "capacity": 1
+      }
+    ]
+    '''
   [cases.shared_ptr_uint64_present]
     param_types = ["std::shared_ptr<std::uint64_t>&"]
     setup = "return std::make_shared<std::uint64_t>(64);"