red code is green: impossible to have 2 signatures with same signature and different primitive return types (IDEA-102866)

(cherry picked from commit c4093d0e8a1021f80fafb3c6b1fc35388da46ac6)

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting6/MethodReturnTypeSubstitutability.java

@@ -0,0 +1,17 @@
+
+interface X4 { Integer m(); }
+interface Y4 { Number m(); }
+interface Z4 extends X4, Y4 {}
+
+interface X1 { long m(); }
+interface Y1 { Number m(); }
+<error descr="'m()' in 'Y1' clashes with 'm()' in 'X1'; methods have unrelated return types">interface Z1 extends X1, Y1</error> {}
+
+interface X2 { long m(); }
+interface Y2 { int m(); }
+<error descr="'m()' in 'X2' clashes with 'm()' in 'Y2'; methods have unrelated return types">interface Z2 extends X2, Y2</error> {}
+
+interface X3 { String m(); }
+interface Y3 { Integer m(); }
+<error descr="'m()' in 'Y3' clashes with 'm()' in 'X3'; methods have unrelated return types">interface Z3 extends X3, Y3</error> {}
+