SCons: Remove unused DEBUG_MEMORY_ENABLED define

Its last use was removed in Godot 3.0, so it no longer makes sense to define.

Also removed `D3D_DEBUG_INFO` for Windows as it's likely a left over from a
long time ago pre-opensourcing when Godot had some form of Direct3D 9 support?

platform/android/detect.py

@@ -164,7 +164,7 @@ def configure(env):
     elif env["target"] == "debug":
         env.Append(LINKFLAGS=["-O0"])
         env.Append(CCFLAGS=["-O0", "-g", "-fno-limit-debug-info"])
-        env.Append(CPPDEFINES=["_DEBUG", "DEBUG_ENABLED", "DEBUG_MEMORY_ENABLED"])
+        env.Append(CPPDEFINES=["_DEBUG", "DEBUG_ENABLED"])
         env.Append(CPPFLAGS=["-UNDEBUG"])
 
     # Compiler configuration