Some DCPs fail to load with skipXdef

[jakobwenzel]

I found a crash inside Design.readCheckpoint.

This works:

        Design.readCheckpoint(RapidWrightDCP.getPath("bug701.dcp"));

This fails:

        Design.readCheckpoint(RapidWrightDCP.getPath("bug701.dcp"), true);

Cannot invoke "com.xilinx.rapidwright.design.SiteInst.setModuleInst(com.xilinx.rapidwright.design.ModuleInst)" because "<local10>" is null
java.lang.NullPointerException: Cannot invoke "com.xilinx.rapidwright.design.SiteInst.setModuleInst(com.xilinx.rapidwright.design.ModuleInst)" because "<local10>" is null
	at com.xilinx.rapidwright.design.ModuleCache.readDesignHierarchy(Unknown Source)
	at c.a(Unknown Source)
	at com.xilinx.rapidwright.design.Design.readCheckpoint(Unknown Source)
	at com.xilinx.rapidwright.design.Design.readCheckpoint(Unknown Source)
	at com.xilinx.rapidwright.design.xdc.TestXDCParser.test(TestXDCParser.java:998)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580)
	at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:688)

[clavin-xlnx]

Thanks, it looks like when loading a DCP that has module instances stored inside, we don't check the skipXdef flag and attempt to load it even though placement and routing has not been loaded. It is an easy fix, but will require a new api-lib jar.