Require "-Xuse-experimental=kotlin.Experimental" on usages of Experimental

Since we're not yet sure of the design of Experimental/UseExperimental,
we're making them "experimental" themselves in some sense, in that the
user is required to provide the magic argument
"-Xuse-experimental=kotlin.Experimental" to be allowed to use either
Experimental or UseExperimental. This is more convenient than the
previous approach of "-language-version 1.3
-Xskip-metadata-version-check" because it's simpler and does not cause
pre-release binaries to be produced

compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestWithStdLibGenerated.java

@@ -2112,6 +2112,11 @@ public class DiagnosticsTestWithStdLibGenerated extends AbstractDiagnosticsTestW
             runTest("compiler/testData/diagnostics/testsWithStdLib/experimental/errors.kt");
         }
 
+        @TestMetadata("experimentalIsNotEnabled.kt")
+        public void testExperimentalIsNotEnabled() throws Exception {
+            runTest("compiler/testData/diagnostics/testsWithStdLib/experimental/experimentalIsNotEnabled.kt");
+        }
+
         @TestMetadata("experimentalOnWholeModule.kt")
         public void testExperimentalOnWholeModule() throws Exception {
             runTest("compiler/testData/diagnostics/testsWithStdLib/experimental/experimentalOnWholeModule.kt");

compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsTestWithStdLibUsingJavacGenerated.java

@@ -2112,6 +2112,11 @@ public class DiagnosticsTestWithStdLibUsingJavacGenerated extends AbstractDiagno
             runTest("compiler/testData/diagnostics/testsWithStdLib/experimental/errors.kt");
         }
 
+        @TestMetadata("experimentalIsNotEnabled.kt")
+        public void testExperimentalIsNotEnabled() throws Exception {
+            runTest("compiler/testData/diagnostics/testsWithStdLib/experimental/experimentalIsNotEnabled.kt");
+        }
+
         @TestMetadata("experimentalOnWholeModule.kt")
         public void testExperimentalOnWholeModule() throws Exception {
             runTest("compiler/testData/diagnostics/testsWithStdLib/experimental/experimentalOnWholeModule.kt");

compiler/tests/org/jetbrains/kotlin/codegen/JvmModuleProtoBufTest.kt

@@ -97,9 +97,7 @@ class JvmModuleProtoBufTest : KtUsefulTestCase() {
     fun testExperimental() {
         doTest(
             "/moduleProtoBuf/experimental", extraOptions = listOf(
-                "-Xskip-runtime-version-check",
-                "-language-version",
-                "1.3",
+                "-Xuse-experimental=kotlin.Experimental",
                 "-Xexperimental=org.foo.A",
                 "-Xexperimental=org.foo.B.C",
                 "-Xuse-experimental=org.foo.D"

compiler/tests/org/jetbrains/kotlin/jvm/compiler/ExperimentalIntegrationTest.kt

@@ -15,29 +15,22 @@ class ExperimentalIntegrationTest : AbstractKotlinCompilerIntegrationTest() {
     fun testJvmExperimentalModule() {
         val lib = compileLibrary(
             "lib", additionalOptions = listOf(
-                "-Xskip-runtime-version-check",
-                "-language-version",
-                "1.3",
+                "-Xuse-experimental=kotlin.Experimental",
                 "-Xexperimental=lib.ExperimentalAPI"
             ),
             checkKotlinOutput = { output -> assertTrue(output, output.trimEnd().endsWith("OK")) }
         )
-        compileKotlin("usage.kt", tmpdir, listOf(lib), additionalOptions = listOf("-Xskip-metadata-version-check"))
+        compileKotlin("usage.kt", tmpdir, listOf(lib))
     }
 
     fun testJsExperimentalModule() {
         val lib = compileJsLibrary(
             "lib", additionalOptions = listOf(
-                "-Xskip-runtime-version-check",
-                "-language-version",
-                "1.3",
+                "-Xuse-experimental=kotlin.Experimental",
                 "-Xexperimental=lib.ExperimentalAPI"
             ),
             checkKotlinOutput = { output -> assertTrue(output, output.trimEnd().endsWith("OK")) }
         )
-        compileKotlin(
-            "usage.kt", File(tmpdir, "usage.js"), listOf(lib), K2JSCompiler(),
-            additionalOptions = listOf("-Xskip-metadata-version-check")
-        )
+        compileKotlin("usage.kt", File(tmpdir, "usage.js"), listOf(lib), K2JSCompiler())
     }
 }