[D3D12] Truncate depth to float24 in EDRAM range ownership transfers and resolves by default

Doesn't ruin the "greater or equal" depth test in subsequent rendering passes if precision is lost, unlike rounding to the nearest

src/xenia/gpu/xenos.cc

@@ -126,7 +126,7 @@ float Float7e3To32(uint32_t f10) {
 // https://github.com/Microsoft/DirectXTex/blob/master/DirectXTex/DirectXTexConvert.cpp
 // 6e4 has a different exponent bias allowing [0,512) values, 20e4 allows [0,2).
 
-uint32_t Float32To20e4(float f32) {
+uint32_t Float32To20e4(float f32, bool round_to_nearest_even) {
   if (!(f32 > 0.0f)) {
     // Positive only, and not -0 or NaN.
     return 0;
@@ -145,7 +145,10 @@ uint32_t Float32To20e4(float f32) {
     // Rebias the exponent to represent the value as a normalized 20e4.
     f32u32 += 0xC8000000u;
   }
-  return ((f32u32 + 3 + ((f32u32 >> 3) & 1)) >> 3) & 0xFFFFFF;
+  if (round_to_nearest_even) {
+    f32u32 += f32u32 + 3 + ((f32u32 >> 3) & 1);
+  }
+  return (f32u32 >> 3) & 0xFFFFFF;
 }
 
 float Float20e4To32(uint32_t f24) {