allocator/Windows: delete the old non-unified allocator-shim

base/BUILD.gn

Index: base/BUILD.gn
diff --git a/base/BUILD.gn b/base/BUILD.gn
index a6c8e51ebee1765526b3964e014186bc0e74785a..42fc780bdeb539566b76b774fea9acbe21675f51 100644
--- a/base/BUILD.gn
+++ b/base/BUILD.gn
@@ -1122,7 +1122,6 @@ component("base") {
   configs += [
     ":base_flags",
     ":base_implementation",
-    "//base/allocator:allocator_shim_define",  # for allocator_check.cc.
     "//build/config:precompiled_headers",
   ]
 
@@ -2292,9 +2291,6 @@ test("base_unittests") {
     ":base_unittests_bundle_data",
   ]
 
-  # Some unittests depend on the ALLOCATOR_SHIM macro.
-  configs += [ "//base/allocator:allocator_shim_define" ]
-
   data = [
     "test/data/",
   ]