Fix v8 Windows GN build.

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index 18e2e1e0050c308eb36c329b6f8d83cb72aadb86..24b1115ed5939cceac4660ac294fc8e99cde5246 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -1059,9 +1059,9 @@ source_set("v8_libbase") {
     # TODO(jochen): Add support for cygwin.
     sources += [
       "src/base/platform/platform-win32.cc",
-      "src/base/platform/win32-headers.h",
-      "src/base/platform/win32-math.cc",
-      "src/base/platform/win32-math.h",
+      "src/base/win32-headers.h",
+      "src/base/win32-math.cc",
+      "src/base/win32-math.h",
     ]
 
     defines += [ "_CRT_RAND_S" ]  # for rand_s()