test: 955 f64 XMM-materialise run + cs==ww byte-id (#103)

Table-driven, modelled on 953: each row does (a) cstage build+run+exit
and (b) w6c vs w6c_ww .s cmp. Rows cover FACE X (0f64 compare false +
true case, 8f64 arith) and FACE Z (tuple-field f64 compare) plus the
let-bound control that was already correct. Fails on master e784968
(x_cmp_false 1!=0, x_arith 100!=80 + byte-id divergence, z_tuple_field
5!=9); passes on the fix.

Makefile

@@ -330,6 +330,7 @@ TESTS	= $(BIN)/test_smoke $(BIN)/test_lex $(BIN)/test_parse $(BIN)/test_check \
 	  $(BIN)/test_f64cgen_run \
 	  $(BIN)/test_f64crossmod_run \
 	  $(BIN)/test_tuprecv_run \
+	  $(BIN)/test_f64xmm_run \
 	  $(BIN)/test_floats_run \
 	  $(BIN)/test_bufio_run $(BIN)/test_random_run
 
@@ -1082,6 +1083,11 @@ $(BIN)/test_tuprecv_run: test/wcc/954_tuprecv_run.c $(BIN)/ww \
 		$(LIB)/libwwrt.a | $(BIN)
 	$(CC) $(CFLAGS) -o $@ $<
 
+$(BIN)/test_f64xmm_run: test/wcc/955_f64xmm_run.c $(BIN)/ww \
+		$(BIN)/w6c $(BIN)/w6c_ww $(BIN)/w6a $(BIN)/w6l \
+		$(LIB)/libwwrt.a | $(BIN)
+	$(CC) $(CFLAGS) -o $@ $<
+
 sizelint:
 	@sh tools/sizelint