LV20: fix LauncherScriptTest testdata

note: the follow-up ussue for one of the changes - KT-60865

compiler/tests/org/jetbrains/kotlin/cli/LauncherScriptTest.kt

@@ -205,7 +205,6 @@ class LauncherScriptTest : TestCaseWithTmpdir() {
             "-a",
             "b",
             expectedStdout = "-a, b\n",
-            expectedStderr = "warning: language version 2.0 is experimental, there are no backwards compatibility guarantees for new language and library features\n"
         )
     }
 
@@ -272,9 +271,6 @@ class LauncherScriptTest : TestCaseWithTmpdir() {
             expectedStderr = """script.kts:1:1: error: unresolved reference: println
 println(42)
 ^
-script.kts:1:1: error: no script runtime was found in the classpath: class 'kotlin.script.templates.standard.ScriptTemplateWithArgs' not found. Please add kotlin-script-runtime.jar to the module dependencies.
-println(42)
-^
 """
         )
     }
@@ -539,7 +535,6 @@ println(42)
             "-cp", ".", "-d", ".", "-language-version", "2.0", file2kt.absolutePath,
             workDirectory = tmpdir,
             expectedStdout = "",
-            expectedStderr = "warning: language version 2.0 is experimental, there are no backwards compatibility guarantees for new language and library features\n"
         )
     }
 }