Remove support for making jemalloc4 the default memory allocator.

memory/replace/logalloc/replay/Replay.cpp

@@ -286,7 +286,7 @@ MOZ_BEGIN_EXTERN_C
 
 /* mozjemalloc relies on DllMain to initialize, but DllMain is not invoked
  * for executables, so manually invoke mozjemalloc initialization. */
-#if defined(_WIN32) && !defined(MOZ_JEMALLOC4)
+#if defined(_WIN32)
 void malloc_init_hard(void);
 #endif
 
@@ -475,7 +475,7 @@ main()
   FdReader reader(0);
   Replay replay;
 
-#if defined(_WIN32) && !defined(MOZ_JEMALLOC4)
+#if defined(_WIN32)
   malloc_init_hard();
 #endif
 

memory/replace/moz.build

@@ -9,9 +9,8 @@ DIRS += [
     'replace',
 ]
 
-# Build jemalloc3 as a replace-malloc lib when building with mozjemalloc
-if not CONFIG['MOZ_JEMALLOC4']:
-    DIRS += ['jemalloc']
+# Build jemalloc4 as a replace-malloc lib when building with mozjemalloc
+DIRS += ['jemalloc']
 
 if CONFIG['MOZ_REPLACE_MALLOC_LINKAGE'] == 'dummy library':
     DIRS += ['dummy']