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_compound_bitops/case.ww

@@ -0,0 +1,9 @@
+//ww:run-exit 96
+// Migrated from 700_e2e row 30.
+package main;
+fn main() i32 = {
+  let x: i32 = 100;
+  x &= 0x3f; x |= 0x80; x ^= 0xc4;
+  x *= 2; x <<= 1; x >>= 2;
+  return x;
+};