use boxed type instead of expected primitive when NULL type is calculated

this allows int -> Integer signature changes when null is passed where primitive is expected (IDEA-164942)

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/changeMethodSignatureFromUsage/afterToBoxedType.java

@@ -0,0 +1,5 @@
+// "Change 1st parameter of method 'bar' from 'int' to 'Integer'" "true"
+ public class Bar {
+     void bar(Integer i) { }
+     { bar(null);}
+ }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/changeMethodSignatureFromUsage/beforeToBoxedType.java

@@ -0,0 +1,5 @@
+// "Change 1st parameter of method 'bar' from 'int' to 'Integer'" "true"
+ public class Bar {
+     void bar(int i) { }
+     { bar(n<caret>ull);}
+ }