Remove redundant check for a variable being initialized after write

It's anyway is obvious for write instruction, while effectively
after optimizations we treat val with syntactic initializer
uninitialized until their immediate initiazer

compiler/testData/diagnostics/tests/controlFlowAnalysis/kt897.kt

@@ -4,7 +4,7 @@ package kt897
 
 class A() {
     init {
-        i = 11
+        <!INITIALIZATION_BEFORE_DECLARATION!>i<!> = 11
     }
     val i : Int? = null // must be an error