x86emul/test: extend cleaning of generated files

Many *.c files are symlinked while building, so along with generated *.h
files they ought to be removed. Conversely $(TARGET) doesn't need removing
twice.

Fixes: cb4fcf70b2 ("x86emul: parallelize SIMD test code building")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>

tools/tests/x86_emulator/Makefile

@@ -261,7 +261,8 @@ $(TARGET): $(OBJS)
 .PHONY: clean
 clean:
 	rm -rf $(TARGET) *.o *~ core *.bin x86_emulate
-	rm -rf $(TARGET) $(addsuffix .h,$(TESTCASES)) $(addsuffix -opmask.h,$(OPMASK))
+	rm -rf $(addsuffix .h,$(TESTCASES)) $(addsuffix -opmask.h,$(OPMASK))
+	rm -rf $(addsuffix .c,$(filter-out blowfish,$(TESTCASES)))
 
 .PHONY: distclean
 distclean: clean