Delete Vulkan/VkDebug.hpp and Vulkan/VkDebug.cpp, use System/Debug.hpp from now on.

Also delete System/DebugAndroid.hpp and System/DebugAndroid.cpp.
These declared yet another version of the debug macros, along with the
AndroidEnterDebugger() function. None of this stuff is actually used
for the Android platform builds, and this change brings in logcat support
to the standard set of macros.

Bug: b/146051794
Change-Id: Ib52ec6af34cdf4ac390c73cb331239d81bed6e06
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/40968
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Tested-by: Ben Clayton <bclayton@google.com>