Simplify and rename function type utilities

- isFunctionType -> change the only usage in TracingStrategyForInvoke to check
  for exact function type
- isExtensionFunctionType -> change all usages to check for exact extension
  function type because extension function types are uninheritable in Kotlin
- isExactFunctionType -> isNonExtensionFunctionType
- isExactExtensionFunctionType -> isExtensionFunctionType
- isExactFunctionOrExtensionFunctionType -> isFunctionType
- isFunctionOrExtensionFunctionType -> isFunctionTypeOrSubtype

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/tower/InvokeProcessors.kt

@@ -16,7 +16,7 @@
 
 package org.jetbrains.kotlin.resolve.calls.tower
 
-import org.jetbrains.kotlin.builtins.isExactExtensionFunctionType
+import org.jetbrains.kotlin.builtins.isExtensionFunctionType
 import org.jetbrains.kotlin.descriptors.FunctionDescriptor
 import org.jetbrains.kotlin.resolve.calls.tasks.ExplicitReceiverKind
 import org.jetbrains.kotlin.resolve.calls.tasks.createSynthesizedInvokes
@@ -25,7 +25,6 @@ import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValue
 import org.jetbrains.kotlin.util.OperatorNameConventions
 import java.util.*
 
-
 abstract class AbstractInvokeTowerProcessor<C>(
         protected val functionContext: TowerContext<C>,
         private val variableProcessor: ScopeTowerProcessor<C>
@@ -141,7 +140,7 @@ private class InvokeExtensionScopeTowerProcessor<C>(
 private fun ScopeTower.getExtensionInvokeCandidateDescriptor(
         extensionFunctionReceiver: ReceiverValue
 ): CandidateWithBoundDispatchReceiver<FunctionDescriptor>? {
-    if (!extensionFunctionReceiver.type.isExactExtensionFunctionType) return null
+    if (!extensionFunctionReceiver.type.isExtensionFunctionType) return null
 
     val invokeDescriptor = extensionFunctionReceiver.type.memberScope.getContributedFunctions(OperatorNameConventions.INVOKE, location).single()
     val synthesizedInvoke = createSynthesizedInvokes(listOf(invokeDescriptor)).single()