[JVM IR] Fix issue where fields are not being set to their default

values within initializer blocks.

The issue occurs in code like this:
```
class C {
  var b = true
  init {
    b = false   // Missing PUTFIELD for this statement
  }
}
```

Added a new statement origin for field initialization (at declaration)
instead of relying on `origin == null` in ExpressionCodegen to determine
whether to generate the initializations.

This was unintentionally broken in
d68a1898d0.

compiler/tests/org/jetbrains/kotlin/codegen/BytecodeTextTestGenerated.java

@@ -339,6 +339,21 @@ public class BytecodeTextTestGenerated extends AbstractBytecodeTextTest {
         runTest("compiler/testData/codegen/bytecodeText/redundantValInitializer.kt");
     }
 
+    @TestMetadata("redundantValInitializerInObject.kt")
+    public void testRedundantValInitializerInObject() throws Exception {
+        runTest("compiler/testData/codegen/bytecodeText/redundantValInitializerInObject.kt");
+    }
+
+    @TestMetadata("redundantVarInitializer.kt")
+    public void testRedundantVarInitializer() throws Exception {
+        runTest("compiler/testData/codegen/bytecodeText/redundantVarInitializer.kt");
+    }
+
+    @TestMetadata("redundantVarInitializerInObject.kt")
+    public void testRedundantVarInitializerInObject() throws Exception {
+        runTest("compiler/testData/codegen/bytecodeText/redundantVarInitializerInObject.kt");
+    }
+
     @TestMetadata("reifiedAsCheck.kt")
     public void testReifiedAsCheck() throws Exception {
         runTest("compiler/testData/codegen/bytecodeText/reifiedAsCheck.kt");