[wasm][cleanup] Remove obsolete AddressHasher

Since address is a uintptr_t, there is no need to implement a specific
hasher.

R=mstarzinger@chromium.org

Bug: v8:7570
Change-Id: I47e652929ef201e742224541d9df4360444e3ba8
Reviewed-on: https://chromium-review.googlesource.com/1044209Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52993}

src/wasm/wasm-code-manager.h

@@ -283,12 +283,6 @@ class V8_EXPORT_PRIVATE NativeModule final {
   friend class NativeModuleDeserializer;
   friend class NativeModuleModificationScope;
 
-  struct AddressHasher {
-    size_t operator()(const Address& addr) const {
-      return std::hash<Address>()(addr);
-    }
-  };
-
   static base::AtomicNumber<size_t> next_id_;
   NativeModule(uint32_t num_functions, uint32_t num_imports,
                bool can_request_more, VirtualMemory* vmem,
@@ -326,7 +320,7 @@ class V8_EXPORT_PRIVATE NativeModule final {
 
   // Maps from instruction start of an immovable code object to instruction
   // start of the trampoline.
-  std::unordered_map<Address, Address, AddressHasher> trampolines_;
+  std::unordered_map<Address, Address> trampolines_;
 
   std::unique_ptr<CompilationState, CompilationStateDeleter> compilation_state_;