Put default value to vars iff they are not boxed

#KT-24672 Fixed

compiler/testData/codegen/bytecodeText/localInitializationLVT/genericsVar.kt

@@ -0,0 +1,18 @@
+// IGNORE_BACKEND: JVM_IR
+
+inline fun <reified T> foo(default: T): T {
+    var t: T
+    run {
+        t = default
+    }
+    return t
+}
+
+fun test() {
+    foo(0.0f)
+}
+
+// two in foo and two in test
+
+// 2 ASTORE 2
+// 1 LOCALVARIABLE t\$iv Lkotlin/jvm/internal/Ref\$ObjectRef; L3 L13 2