[FIR] Add checker for uninitialized properties

compiler/testData/diagnostics/testsWithStdLib/contracts/controlflow/flowInlining/labeledReturns.fir.kt

@@ -44,7 +44,7 @@ fun threeLevelsReturnNoInitialization(x: Int?): Int? {
         // Possible to report unreachable here
         y = 54
     }
-    return y.inc()
+    return <!UNINITIALIZED_VARIABLE!>y<!>.inc()
 }
 
 fun threeLevelsReturnWithInitialization(x: Int?): Int? {
@@ -82,5 +82,5 @@ fun threeLevelsReturnWithUnknown(x: Int?): Int? {
             }
         }
     }
-    return y.inc()
+    return <!UNINITIALIZED_VARIABLE!>y<!>.inc()
 }

compiler/testData/diagnostics/testsWithStdLib/contracts/controlflow/flowInlining/nestedTryCatchFinally.fir.kt

@@ -36,7 +36,7 @@ fun outerFinallyInitializes() {
         x = outerComputation()
     } catch (e: java.lang.Exception) {
         // can catch exception thrown by the inner, so x can be not initialized
-        x.inc()
+        <!UNINITIALIZED_VARIABLE!>x<!>.inc()
         log()
     } finally {
         // Possible reassignment (e.g. if everything finished)

compiler/testData/diagnostics/testsWithStdLib/contracts/controlflow/flowInlining/nestedTryCatchs.fir.kt

@@ -37,7 +37,7 @@ fun innerTryCatchInitializes() {
         // Can get here if innerComputation() threw an exception that wasn't catched by the inner catch (x is not initialized)
         // OR if outerComputation() threw an exception (x is initialized because we reach outer computation only when inner finished ok)
         // So, x=I? here
-        x.inc()
+        <!UNINITIALIZED_VARIABLE!>x<!>.inc()
 
         // Potential reasignment
         x = 42

compiler/testData/diagnostics/testsWithStdLib/contracts/controlflow/flowInlining/nonReturningInlinedLambda.fir.kt

@@ -21,7 +21,7 @@ fun withLabeledReturn() {
         y = 42
     }
 
-    println(y)
+    println(<!UNINITIALIZED_VARIABLE!>y<!>)
     println(x)
 }
 

compiler/testData/diagnostics/testsWithStdLib/contracts/controlflow/flowInlining/severalJumpOutsFromInlinedLambda.fir.kt

@@ -33,7 +33,7 @@ fun exitOnlyThroughLocalReturns(b: Boolean) {
     }
 
     x.inc()
-    s.length
+    <!UNINITIALIZED_VARIABLE!>s<!>.length
 }
 
 fun exitOnlyThroughNonLocalReturns(b: Boolean?) {
@@ -49,7 +49,7 @@ fun exitOnlyThroughNonLocalReturns(b: Boolean?) {
             x = 54
         }
 
-        if (x == 42) {
+        if (<!UNINITIALIZED_VARIABLE!>x<!> == 42) {
             return
         }
         else {
@@ -59,8 +59,8 @@ fun exitOnlyThroughNonLocalReturns(b: Boolean?) {
         }
     }
 
-    x.inc()
-    s.length
+    <!UNINITIALIZED_VARIABLE!>x<!>.inc()
+    <!UNINITIALIZED_VARIABLE!>s<!>.length
 }
 
 fun nonLocalReturnAndOrdinaryExit(b: Boolean) {

compiler/testData/diagnostics/testsWithStdLib/contracts/controlflow/flowInlining/throwIfNotCalled.fir.kt

@@ -44,5 +44,5 @@ fun catchThrowIfNotCalled() {
     } catch (ignored: java.lang.IllegalArgumentException) { }
 
     // x *isn't* initialized here!
-    println(x)
+    println(<!UNINITIALIZED_VARIABLE!>x<!>)
 }

compiler/testData/diagnostics/testsWithStdLib/contracts/controlflow/flowInlining/tryCatch.fir.kt

@@ -22,7 +22,7 @@ fun tryCatchInlined() {
             x.inc()
         }
         catch (e: java.lang.Exception) {
-            x.inc()
+            <!UNINITIALIZED_VARIABLE!>x<!>.inc()
         }
     }
     x = 42