Condense namespaces in tint/fuzzers.

This PR condenses the namespaces in the tint/fuzzers folder.

Change-Id: I74d4db39e41d408a826bee89241c5752e1aa7df9
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/86036
Reviewed-by: Ben Clayton <bclayton@google.com>
Auto-Submit: Dan Sinclair <dsinclair@chromium.org>
Commit-Queue: Dan Sinclair <dsinclair@chromium.org>
diff --git a/src/tint/fuzzers/random_generator_engine.cc b/src/tint/fuzzers/random_generator_engine.cc
index 2e861e3..d171788 100644
--- a/src/tint/fuzzers/random_generator_engine.cc
+++ b/src/tint/fuzzers/random_generator_engine.cc
@@ -14,13 +14,11 @@
 
 #include "src/tint/fuzzers/random_generator_engine.h"
 
-namespace tint {
-namespace fuzzers {
+namespace tint::fuzzers {
 
 // Not in header to avoid weak vtable warnings from clang
 RandomGeneratorEngine::RandomGeneratorEngine() = default;
 RandomGeneratorEngine::~RandomGeneratorEngine() = default;
 RandomGeneratorEngine::RandomGeneratorEngine(RandomGeneratorEngine&&) = default;
 
-}  // namespace fuzzers
-}  // namespace tint
+}  // namespace tint::fuzzers