Remove backend tests on old inference

Also remove any mentions of NewInference, and rename some tests.

compiler/testData/codegen/box/inference/builderInference.kt

@@ -1,6 +1,5 @@
 // TARGET_BACKEND: JVM
 // WITH_RUNTIME
-// !LANGUAGE: +NewInference
 // ISSUE: KT-33545
 
 import kotlin.experimental.ExperimentalTypeInference
@@ -29,4 +28,4 @@ fun <Value> Flow<Value>.asLiveData() = liveData {
 //    collect { emit(it) }
 }
 
-fun box(): String = "OK"
+fun box(): String = "OK"

compiler/testData/codegen/box/inference/builderInference/callableReferenceAndCoercionToUnit.kt

@@ -1,4 +1,3 @@
-// !LANGUAGE: +NewInference
 // !DIAGNOSTICS: -OPT_IN_USAGE_ERROR -UNUSED_EXPRESSION
 // WITH_RUNTIME
 

compiler/testData/codegen/box/inference/builderInference/lackOfNullCheckOnNullableInsideBuild.kt

@@ -1,4 +1,3 @@
-// !LANGUAGE: +NewInference
 // WITH_RUNTIME
 // Issue: KT-36371
 

compiler/testData/codegen/box/inference/builderInference/specialCallsWithCallableReferencesNonStrictOnlyInputTypes.kt

@@ -1,4 +1,3 @@
-// !LANGUAGE: +NewInference
 // WITH_RUNTIME
 // TARGET_BACKEND: JVM
 // IGNORE_BACKEND: WASM
@@ -24,4 +23,4 @@ interface Flow<out T>
 
 interface FlowCollector<in T>
 
-fun box() = "OK"
+fun box() = "OK"

compiler/testData/codegen/box/inference/builderInferenceLeakingVariable.kt

@@ -1,6 +1,5 @@
 // Issues: KT-33542, KT-33544
 // WITH_RUNTIME
-// !LANGUAGE: +NewInference
 
 import kotlin.experimental.ExperimentalTypeInference
 

compiler/testData/codegen/box/inference/capturedStarProjection.kt

@@ -1,4 +1,3 @@
-// !LANGUAGE: +NewInference
 // WITH_RUNTIME
 
 interface A<T> {
@@ -11,4 +10,4 @@ fun test(a: A<*>) {
 
 fun box(): String {
     return "OK"
-}
+}

compiler/testData/codegen/box/inference/integerLiteralTypeInLamdaReturnType.kt

@@ -1,4 +1,3 @@
-// !LANGUAGE: +NewInference
 // WITH_RUNTIME
 // SKIP_DCE_DRIVEN
 
@@ -15,4 +14,4 @@ fun box(): String {
     val sorted = foo.test(list)
 
     return list.first()
-}
+}

compiler/testData/codegen/box/inference/kt32429.kt

@@ -1,6 +1,5 @@
 // TARGET_BACKEND: JVM
 // WITH_RUNTIME
-// !LANGUAGE: +NewInference
 // ISSUE: KT-32429
 
 import kotlin.properties.Delegates.observable

compiler/testData/codegen/box/inference/kt35684.kt

@@ -1,4 +1,3 @@
-// !LANGUAGE: +NewInference
 // !OPT_IN: kotlin.RequiresOptIn
 // WITH_RUNTIME
 

compiler/testData/codegen/box/inference/kt36446.kt

@@ -1,4 +1,3 @@
-// !LANGUAGE: +NewInference
 // WITH_RUNTIME
 // WITH_REFLECT
 

compiler/testData/codegen/box/inference/lastExpressionOfLambdaWithNothingConstraint.kt

@@ -1,4 +1,3 @@
-// !LANGUAGE: +NewInference
 // WITH_RUNTIME
 
 inline fun <T> foo(f: () -> T): String {
@@ -27,4 +26,4 @@ fun test(b: Boolean): String {
 
 fun box(): String {
     return test(true)
-}
+}

compiler/testData/codegen/box/inference/suspendExtensionRecevierFromConstraint.kt

@@ -1,5 +1,4 @@
 // WITH_RUNTIME
-// !LANGUAGE: +NewInference
 
 class ExtensionReceiver
 typealias SuspendExtensionFunction = suspend ExtensionReceiver.() -> Unit