test: migrate 700_e2e rows to corpus fixtures; retire the carrier

136 rows migrated, 0 already owned, 3 wwstage-failing rows held out.

test/wcc/data/r700_enum_bitor/case.ww

@@ -0,0 +1,8 @@
+//ww:run-exit 3
+// Migrated from 700_e2e row 117.
+package main;
+type mode = enum u8 { R = 1, W = 2 };
+fn main() i32 = {
+  let m: mode = mode.R | mode.W;
+  return m as i32;
+};