Remove some remaining tests on old coroutines

compiler/testData/codegen/bytecodeListing/main/suspendMain_before.kt

@@ -1,8 +0,0 @@
-// !LANGUAGE: -ExtendedMainConvention -ReleaseCoroutines
-// Does not run on JVM_IR since it uses experimental coroutines
-// IGNORE_BACKEND: JVM_IR
-// WITH_RUNTIME
-
-// uses kotlin.coroutines.experimental classes under the hood
-
-suspend fun main(args: Array<String>) {}

compiler/testData/codegen/bytecodeListing/main/suspendMain_before.txt

@@ -1,5 +0,0 @@
-@kotlin.Metadata
-public final class SuspendMain_beforeKt {
-    // source: 'suspendMain_before.kt'
-    public final static @org.jetbrains.annotations.Nullable method main(@org.jetbrains.annotations.NotNull p0: java.lang.String[], @org.jetbrains.annotations.NotNull p1: kotlin.coroutines.experimental.Continuation): java.lang.Object
-}