tint: Fix compilation error with latest MSVC 17.5.0

Not sure if MSVC is wrong here, but it now fails to compile this file
because it looks for `builtin::AddressSpace::kPrivate` within the inner
`builtin` namespace, rather than in `tint::builtin`.

Change-Id: I10f9e1bd58e6ba548d40823f03802320865f069d
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/121221
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>
diff --git a/src/tint/resolver/side_effects_test.cc b/src/tint/resolver/side_effects_test.cc
index b7027d1..f6ce399 100644
--- a/src/tint/resolver/side_effects_test.cc
+++ b/src/tint/resolver/side_effects_test.cc
@@ -129,7 +129,7 @@
     EXPECT_TRUE(sem->HasSideEffects());
 }
 
-namespace builtin {
+namespace builtin_tests {
 struct Case {
     const char* name;
     utils::Vector<const char*, 3> args;
@@ -368,7 +368,7 @@
         // C("saturate", utils::Vector{"f"}, false), //
     }));
 
-}  // namespace builtin
+}  // namespace builtin_tests
 
 TEST_F(SideEffectsTest, Call_Function) {
     Func("f", utils::Empty, ty.i32(), utils::Vector{Return(1_i)});