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_f64_compound_local/case.ww

@@ -0,0 +1,11 @@
+//ww:run-exit 2
+// Migrated from 700_e2e row 119.
+package main;
+fn main() i32 = {
+  let a: f64 = 1.5;
+  a += 0.5;
+  a -= 1.0;
+  a *= 4.0;
+  a /= 2.0;
+  return a: i32;
+};