let exact prefix items be the ones that have exact prefix as any lookup string, not just the main one (IDEA-168948)

java/java-tests/testData/codeInsight/completion/normalSorting/PreferExpectedTypeConstantOverClass.java

@@ -0,0 +1,11 @@
+class SomeClass {
+  void foo(Point p) {
+    p.smth(JSON<caret>);
+  }
+}
+
+interface Point {
+  int FOO = 2;
+  int JSON = 3;
+  void smth(int x);
+}

java/java-tests/testData/codeInsight/completion/normalSorting/PreferExpectedTypeConstantOverSameNamedClass.java

@@ -0,0 +1,11 @@
+class SomeClass {
+  void foo(Point p) {
+    p.smth(JSON<caret>);
+  }
+}
+
+interface Point {
+  int FOO = 2;
+  int JSON = 3;
+  void smth(int x);
+}