Reland of "Remove ExternalArray, derived types, and element kinds"

src/contexts.h

Index: src/contexts.h
diff --git a/src/contexts.h b/src/contexts.h
index fc29831942645a8cce99de3472e4908b178df8d2..37fc31565c1937a172f2cd174ea50e694e9a7172 100644
--- a/src/contexts.h
+++ b/src/contexts.h
@@ -115,16 +115,6 @@ enum BindingFlags {
   V(FLOAT32_ARRAY_FUN_INDEX, JSFunction, float32_array_fun)                    \
   V(FLOAT64_ARRAY_FUN_INDEX, JSFunction, float64_array_fun)                    \
   V(UINT8_CLAMPED_ARRAY_FUN_INDEX, JSFunction, uint8_clamped_array_fun)        \
-  V(INT8_ARRAY_EXTERNAL_MAP_INDEX, Map, int8_array_external_map)               \
-  V(UINT8_ARRAY_EXTERNAL_MAP_INDEX, Map, uint8_array_external_map)             \
-  V(INT16_ARRAY_EXTERNAL_MAP_INDEX, Map, int16_array_external_map)             \
-  V(UINT16_ARRAY_EXTERNAL_MAP_INDEX, Map, uint16_array_external_map)           \
-  V(INT32_ARRAY_EXTERNAL_MAP_INDEX, Map, int32_array_external_map)             \
-  V(UINT32_ARRAY_EXTERNAL_MAP_INDEX, Map, uint32_array_external_map)           \
-  V(FLOAT32_ARRAY_EXTERNAL_MAP_INDEX, Map, float32_array_external_map)         \
-  V(FLOAT64_ARRAY_EXTERNAL_MAP_INDEX, Map, float64_array_external_map)         \
-  V(UINT8_CLAMPED_ARRAY_EXTERNAL_MAP_INDEX, Map,                               \
-    uint8_clamped_array_external_map)                                          \
   V(DATA_VIEW_FUN_INDEX, JSFunction, data_view_fun)                            \
   V(SLOPPY_FUNCTION_MAP_INDEX, Map, sloppy_function_map)                       \
   V(SLOPPY_FUNCTION_WITH_READONLY_PROTOTYPE_MAP_INDEX, Map,                    \