FIR: Rewrite Java type mapping

Previoisly, there were two places where mapping had happened:
- toConeKotlinTypeWithNullability
- enhancePossiblyFlexible

The first one was used for supertypes and bounds and the second one
was used for other signature parts

The main idea is to perform type mapping once to a flexible type,
and then use it as it's needed (it's lower bound, or for the further ehnancement)

Also, this commit fixes flexibility for type arguments, see the tests

compiler/testData/loadJava/compiledJava/sam/GenericInterfaceParameterWithSelfBound.fir.txt

@@ -1,4 +1,4 @@
-public abstract interface GenericInterfaceParameterWithSelfBound<T : R|ft<test/GenericInterfaceParameterWithSelfBound<T>, test/GenericInterfaceParameterWithSelfBound<T>?>!|> : R|kotlin/Any| {
+public abstract interface GenericInterfaceParameterWithSelfBound<T : R|ft<test/GenericInterfaceParameterWithSelfBound<ft<T, T?>!>, test/GenericInterfaceParameterWithSelfBound<ft<T, T?>!>?>!|> : R|kotlin/Any| {
     public abstract operator fun method(t: R|ft<T, T?>!|): R|ft<T, T?>!|
 
 }

compiler/testData/loadJava/compiledJava/sam/GenericInterfaceParametersWithBounds.fir.txt

@@ -1,4 +1,4 @@
-public abstract interface GenericInterfaceParametersWithBounds<A : R|ft<kotlin/Comparable<A>, kotlin/Comparable<A>?>!|, R|ft<kotlin/Cloneable, kotlin/Cloneable?>!|, B : R|ft<kotlin/collections/MutableList<A>, kotlin/collections/MutableList<A>?>!|> : R|kotlin/Any| {
+public abstract interface GenericInterfaceParametersWithBounds<A : R|ft<kotlin/Comparable<ft<A, A?>!>, kotlin/Comparable<ft<A, A?>!>?>!|, R|ft<kotlin/Cloneable, kotlin/Cloneable?>!|, B : R|ft<kotlin/collections/MutableList<ft<A, A?>!>, kotlin/collections/List<ft<A, A?>!>?>!|> : R|kotlin/Any| {
     public abstract operator fun method(a: R|ft<kotlin/Array<ft<A, A?>!>, kotlin/Array<out ft<A, A?>!>?>!|, b: R|ft<B, B?>!|): R|kotlin/Unit|
 
 }

compiler/testData/loadJava/compiledJava/sam/GenericMethodParameters.fir.txt

@@ -1,4 +1,4 @@
 public abstract interface GenericMethodParameters : R|kotlin/Any| {
-    public abstract operator fun <A : R|ft<kotlin/CharSequence, kotlin/CharSequence?>!|, B : R|ft<kotlin/collections/MutableList<A>, kotlin/collections/MutableList<A>?>!|> method(a: R|ft<kotlin/Array<ft<A, A?>!>, kotlin/Array<out ft<A, A?>!>?>!|, b: R|ft<B, B?>!|): R|kotlin/Unit|
+    public abstract operator fun <A : R|ft<kotlin/CharSequence, kotlin/CharSequence?>!|, B : R|ft<kotlin/collections/MutableList<ft<A, A?>!>, kotlin/collections/List<ft<A, A?>!>?>!|> method(a: R|ft<kotlin/Array<ft<A, A?>!>, kotlin/Array<out ft<A, A?>!>?>!|, b: R|ft<B, B?>!|): R|kotlin/Unit|
 
 }

compiler/testData/loadJava/compiledJava/sam/adapters/NonTrivialFunctionType.fir.txt

@@ -5,7 +5,7 @@ public open class NonTrivialFunctionType : R|kotlin/Any| {
 
     public open operator fun wildcardUnbound(comparator: R|ft<java/util/Comparator<*>, java/util/Comparator<*>?>!|): R|kotlin/Unit|
 
-    public open operator fun wildcardBound(comparator: R|ft<java/util/Comparator<in kotlin/CharSequence>, java/util/Comparator<in kotlin/CharSequence>?>!|): R|kotlin/Unit|
+    public open operator fun wildcardBound(comparator: R|ft<java/util/Comparator<in ft<kotlin/CharSequence, kotlin/CharSequence?>!>, java/util/Comparator<in ft<kotlin/CharSequence, kotlin/CharSequence?>!>?>!|): R|kotlin/Unit|
 
     public constructor(): R|test/NonTrivialFunctionType|
 

compiler/testData/loadJava/compiledJava/sam/adapters/TypeParameterOfMethod.fir.txt

@@ -3,7 +3,7 @@ public open class TypeParameterOfMethod : R|kotlin/Any| {
 
     public open static operator fun <T : R|ft<kotlin/CharSequence, kotlin/CharSequence?>!|> max2(comparator: R|ft<java/util/Comparator<ft<T, T?>!>, java/util/Comparator<ft<T, T?>!>?>!|, value1: R|ft<T, T?>!|, value2: R|ft<T, T?>!|): R|ft<T, T?>!|
 
-    public open static operator fun <A : R|ft<kotlin/CharSequence, kotlin/CharSequence?>!|, B : R|ft<kotlin/collections/MutableList<A>, kotlin/collections/MutableList<A>?>!|> method(a: R|ft<java/util/Comparator<ft<A, A?>!>, java/util/Comparator<ft<A, A?>!>?>!|, b: R|ft<B, B?>!|): R|kotlin/Unit|
+    public open static operator fun <A : R|ft<kotlin/CharSequence, kotlin/CharSequence?>!|, B : R|ft<kotlin/collections/MutableList<ft<A, A?>!>, kotlin/collections/List<ft<A, A?>!>?>!|> method(a: R|ft<java/util/Comparator<ft<A, A?>!>, java/util/Comparator<ft<A, A?>!>?>!|, b: R|ft<B, B?>!|): R|kotlin/Unit|
 
     public constructor(): R|test/TypeParameterOfMethod|