A DESCRIPTION OF THE PROBLEM :
Relates to JDK-8263642, possibly introduced by JDK-8209022

When an intersection type cast, e.g. `I1 & I2`, is used and the result of it is then used in a way where the expected type is one of the intersection type supertypes other then the first, e.g. `I2`, a duplicate `checkcast` is emitted for this type.

However, maybe this is a rare corner case which never actually occurs in reality because such Java source code makes no sense. And care must be taken to not reintroduce JDK-8209022.

REGRESSION : Last worked in version 11.0.11

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Create a source file `IntersectionTypeTest.java` with the code provided below
2. Compile it
3. Inspect the bytecode, e.g. using `javap -v`

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
No duplicate `checkcast`
ACTUAL -
There are duplicate checkcasts e.g. here for `I2`:
void testSecond();
    descriptor: ()V
    flags: (0x0000)
    Code:
      stack=2, locals=2, args_size=1
         0: new #7 // class IntersectionTypeTest$C
         3: dup
         4: invokespecial #9 // Method IntersectionTypeTest$C."<init>":()V
         7: checkcast #10 // class IntersectionTypeTest$I2
        10: checkcast #12 // class IntersectionTypeTest$I3
        13: checkcast #14 // class IntersectionTypeTest$I1
        16: checkcast #10 // class IntersectionTypeTest$I2

---------- BEGIN SOURCE ----------
class IntersectionTypeTest {
    interface I1 { }
    interface I2 { }
    interface I3 { }
    static class C { }
   
    void testFirst() {
        // No duplicate checkcast; first intersection type supertype is same as variable type
        I1 i = (I1 & I2 & I3) new C();
    }
    
    void testSecond() {
        // Duplicate checkcast for `I2`
        I2 i = (I1 & I2 & I3) new C();
    }
    
    I3 testThirdReturn() {
        // Also affects for example `return` statement; duplicate `checkcast` for `I3`
        return (I1 & I2 & I3) new C();
    }
}
---------- END SOURCE ----------