Fixed recent Decompiler location regressions

Ghidra/Features/Decompiler/src/main/java/ghidra/app/decompiler/location/FunctionNameDecompilerLocation.java

@@ -37,6 +37,11 @@ public class FunctionNameDecompilerLocation extends FunctionNameFieldLocation
 		this.info = info;
 	}
 
+	public FunctionNameDecompilerLocation() {
+		// for restoring from xml
+		info = new DecompilerLocationInfo();
+	}
+
 	@Override
 	public Address getFunctionEntryPoint() {
 		return info.getFunctionEntryPoint();

Ghidra/Features/Decompiler/src/main/java/ghidra/app/decompiler/location/VariableDecompilerLocation.java

@@ -38,6 +38,11 @@ public class VariableDecompilerLocation extends VariableLocFieldLocation
 		this.info = info;
 	}
 
+	public VariableDecompilerLocation() {
+		// for restoring from xml
+		info = new DecompilerLocationInfo();
+	}
+
 	@Override
 	public Address getFunctionEntryPoint() {
 		return info.getFunctionEntryPoint();

Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/pcode/HighFunctionDBUtil.java

@@ -517,6 +517,10 @@ public class HighFunctionDBUtil {
 
 	public static Variable getFunctionVariable(HighSymbol highSymbol) {
 
+		if (highSymbol == null) {
+			return null;
+		}
+
 		HighFunction highFunction = highSymbol.getHighFunction();
 		Function function = highFunction.getFunction();
 		HighVariable highVar = highSymbol.getHighVariable();