Use new sequence builders in tests

Coroutine tests will fail when LV=1.2 because there're no such builders
in kotlin.coroutines.experimental.

#KT-26678

compiler/testData/codegen/box/coroutines/controlFlow/kt22694.kt

@@ -5,7 +5,6 @@
 // COMMON_COROUTINES_TEST
 import helpers.*
 import COROUTINES_PACKAGE.*
-import COROUTINES_PACKAGE.intrinsics.*
 
 enum class Foo(vararg expected: String) {
     A("start", "A", "end"),
@@ -30,7 +29,7 @@ fun box(): String {
 }
 
 fun getSequence(a: Foo) =
-    buildSequence {
+    sequence {
         yield("start")
         when (a) {
             Foo.A -> {

compiler/testData/codegen/box/coroutines/suspendFunctionAsCoroutine/ifExpressionInsideCoroutine.kt

@@ -5,10 +5,9 @@
 // COMMON_COROUTINES_TEST
 import helpers.*
 import COROUTINES_PACKAGE.*
-import COROUTINES_PACKAGE.intrinsics.*
 
 val f = run {
-    buildSequence {
+    sequence {
         if (true) {
             yield("OK")
         }

compiler/testData/codegen/bytecodeText/coroutines/debug/localVariableCorrectLabel.kt

@@ -1,10 +1,9 @@
 // LANGUAGE_VERSION: 1.3
 
-import kotlin.coroutines.*
 import kotlin.sequences.*
 
 fun main(args: Array<String>) {
-    val s = buildSequence {
+    val s = sequence {
         yield(1)
         val a = awaitSeq()
         println(a) // (1)
@@ -12,7 +11,7 @@ fun main(args: Array<String>) {
     println(s.toList())
 }
 
-suspend fun SequenceBuilder<Int>.awaitSeq(): Int = 42
+suspend fun SequenceScope<Int>.awaitSeq(): Int = 42
 
 // 1 LOCALVARIABLE a I L18 L22 3
-// 1 LINENUMBER 10 L18
+// 1 LINENUMBER 9 L18