Refactor LateinitLowering into DeclarationTransformer's and a BodyLoweringPass

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/WasmLoweringPhases.kt

@@ -71,12 +71,25 @@ private val expectDeclarationsRemovingPhase = makeWasmModulePhase(
     description = "Remove expect declaration from module fragment"
 )
 
-private val lateinitLoweringPhase = makeWasmModulePhase(
-    ::LateinitLowering,
-    name = "LateinitLowering",
+private val lateinitNullableFieldsPhase = makeWasmModulePhase(
+    ::NullableFieldsForLateinitCreationLowering,
+    name = "LateinitNullableFields",
+    description = "Create nullable fields for lateinit properties"
+)
+
+private val lateinitDeclarationLoweringPhase = makeWasmModulePhase(
+    ::NullableFieldsDeclarationLowering,
+    name = "LateinitDeclarations",
+    description = "Reference nullable fields from properties and getters + insert checks"
+)
+
+private val lateinitUsageLoweringPhase = makeWasmModulePhase(
+    ::LateinitUsageLowering,
+    name = "LateinitUsage",
     description = "Insert checks for lateinit field references"
 )
 
+
 // TODO make all lambda-related stuff work with IrFunctionExpression and drop this phase
 private val provisionalFunctionExpressionPhase = makeWasmModulePhase(
     { ProvisionalFunctionExpressionLowering() },
@@ -329,7 +342,9 @@ val wasmPhases = namedIrModulePhase<WasmBackendContext>(
             // arrayConstructorPhase then
 
             functionInliningPhase then
-            lateinitLoweringPhase then
+            lateinitNullableFieldsPhase then
+            lateinitDeclarationLoweringPhase then
+            lateinitUsageLoweringPhase then
             tailrecLoweringPhase then
 
             enumClassConstructorLoweringPhase then