Support "align-content: space-evenly"

Summary:
### Changes made
- Regenerated tests (as some aspect ratio tests seem to be out of date compared to the fixtures)
- Added SpaceEvenly variant to the "Align" enums (via enums.py)
- Implemented `align-content: space-evenly` alignment in CalculateLayout.cpp
- Added generated tests `align-content: space-evenly`
- Updated NumericBitfield test to account for the fact that the Align enum now requires more bits (this bit could do with being reviewed as I am not 100% certain that it's valid to just update the test like this).

### Changes not made
- Any attempt to improve the spec-compliance of content alignment in general (e.g. I think facebook/yoga#1013 probably still needs to happen)

X-link: facebook/yoga#1422

Differential Revision: D50305438

Pulled By: NickGerleman

fbshipit-source-id: e3424c98e82b35300561eca22f636ff9e1593dee

Author: nicoburns

packages/react-native/ReactAndroid/src/main/java/com/facebook/yoga/YogaAlign.java

@@ -17,7 +17,8 @@ public enum YogaAlign {
   STRETCH(4),
   BASELINE(5),
   SPACE_BETWEEN(6),
-  SPACE_AROUND(7);
+  SPACE_AROUND(7),
+  SPACE_EVENLY(8);
 
   private final int mIntValue;
 
@@ -39,6 +40,7 @@ public static YogaAlign fromInt(int value) {
       case 5: return BASELINE;
       case 6: return SPACE_BETWEEN;
       case 7: return SPACE_AROUND;
+      case 8: return SPACE_EVENLY;
       default: throw new IllegalArgumentException("Unknown enum value: " + value);
     }
   }

packages/react-native/ReactCommon/react/renderer/components/view/conversions.h

@@ -747,41 +747,11 @@ inline std::string toString(const yoga::FlexDirection& value) {
 }
 
 inline std::string toString(const yoga::Justify& value) {
-  switch (value) {
-    case yoga::Justify::FlexStart:
-      return "flex-start";
-    case yoga::Justify::Center:
-      return "center";
-    case yoga::Justify::FlexEnd:
-      return "flex-end";
-    case yoga::Justify::SpaceBetween:
-      return "space-between";
-    case yoga::Justify::SpaceAround:
-      return "space-around";
-    case yoga::Justify::SpaceEvenly:
-      return "space-evenly";
-  }
+  return YGJustifyToString(yoga::unscopedEnum(value));
 }
 
 inline std::string toString(const yoga::Align& value) {
-  switch (value) {
-    case yoga::Align::Auto:
-      return "auto";
-    case yoga::Align::FlexStart:
-      return "flex-start";
-    case yoga::Align::Center:
-      return "center";
-    case yoga::Align::FlexEnd:
-      return "flex-end";
-    case yoga::Align::Stretch:
-      return "stretch";
-    case yoga::Align::Baseline:
-      return "baseline";
-    case yoga::Align::SpaceBetween:
-      return "space-between";
-    case yoga::Align::SpaceAround:
-      return "space-around";
-  }
+  return YGAlignToString(yoga::unscopedEnum(value));
 }
 
 inline std::string toString(const yoga::PositionType& value) {

packages/react-native/ReactCommon/yoga/yoga/YGEnums.cpp

@@ -27,6 +27,8 @@ const char* YGAlignToString(const YGAlign value) {
       return "space-between";
     case YGAlignSpaceAround:
       return "space-around";
+    case YGAlignSpaceEvenly:
+      return "space-evenly";
   }
   return "unknown";
 }

packages/react-native/ReactCommon/yoga/yoga/YGEnums.h

@@ -21,7 +21,8 @@ YG_ENUM_SEQ_DECL(
     YGAlignStretch,
     YGAlignBaseline,
     YGAlignSpaceBetween,
-    YGAlignSpaceAround)
+    YGAlignSpaceAround,
+    YGAlignSpaceEvenly)
 
 YG_ENUM_SEQ_DECL(
     YGDimension,

packages/react-native/ReactCommon/yoga/yoga/algorithm/CalculateLayout.cpp

@@ -2021,6 +2021,18 @@ static void calculateLayoutImpl(
             currentLead += remainingAlignContentDim / 2;
           }
           break;
+        case Align::SpaceEvenly:
+          if (availableInnerCrossDim > totalLineCrossDim) {
+            currentLead +=
+                remainingAlignContentDim / static_cast<float>(lineCount + 1);
+            if (lineCount > 1) {
+              crossDimLead =
+                  remainingAlignContentDim / static_cast<float>(lineCount + 1);
+            }
+          } else {
+            currentLead += remainingAlignContentDim / 2;
+          }
+          break;
         case Align::SpaceBetween:
           if (availableInnerCrossDim > totalLineCrossDim && lineCount > 1) {
             crossDimLead =
@@ -2177,6 +2189,7 @@ static void calculateLayoutImpl(
               case Align::Auto:
               case Align::SpaceBetween:
               case Align::SpaceAround:
+              case Align::SpaceEvenly:
                 break;
             }
           }

packages/react-native/ReactCommon/yoga/yoga/enums/Align.h

@@ -24,16 +24,17 @@ enum class Align : uint8_t {
   Baseline = YGAlignBaseline,
   SpaceBetween = YGAlignSpaceBetween,
   SpaceAround = YGAlignSpaceAround,
+  SpaceEvenly = YGAlignSpaceEvenly,
 };
 
 template <>
 constexpr inline int32_t ordinalCount<Align>() {
-  return 8;
+  return 9;
 } 
 
 template <>
 constexpr inline int32_t bitCount<Align>() {
-  return 3;
+  return 4;
 } 
 
 constexpr inline Align scopedEnum(YGAlign unscoped) {