Fix === comparison for primitive types

#KT-6590 Fixed

compiler/testData/codegen/box/primitiveTypes/kt6590_identityEquals.kt

@@ -0,0 +1,15 @@
+fun box(): String {
+    val i: Int = 10000
+    if (!(i === i)) return "Fail int ==="
+    if (i !== i) return "Fail int !=="
+
+    val j: Long = 123L
+    if (!(j === j)) return "Fail long ==="
+    if (j !== j) return "Fail long !=="
+
+    val d: Double = 3.14
+    if (!(d === d)) return "Fail double ==="
+    if (d !== d) return "Fail double !=="
+
+    return "OK"
+}