Add Kotlin 1.7 language version

compiler/testData/cli/jvm/apiVersionInvalid.out

@@ -1,3 +1,3 @@
 error: unknown API version: 239.42
-Supported API versions: 1.3 (DEPRECATED), 1.4, 1.5, 1.6 (EXPERIMENTAL)
+Supported API versions: 1.3 (DEPRECATED), 1.4, 1.5, 1.6 (EXPERIMENTAL), 1.7 (EXPERIMENTAL)
 COMPILATION_ERROR

compiler/testData/cli/jvm/languageVersionInvalid.out

@@ -1,3 +1,3 @@
 error: unknown language version: 239.42
-Supported language versions: 1.3 (DEPRECATED), 1.4, 1.5, 1.6 (EXPERIMENTAL)
+Supported language versions: 1.3 (DEPRECATED), 1.4, 1.5, 1.6 (EXPERIMENTAL), 1.7 (EXPERIMENTAL)
 COMPILATION_ERROR

compiler/testData/codegen/bytecodeText/inlineClasses/resultApiEqualsDoesntBox.kt

@@ -1,4 +1,4 @@
-// !API_VERSION: LATEST
+// !API_VERSION: LATEST_STABLE
 // WITH_RUNTIME
 // FILE: test.kt
 fun test() {

compiler/testData/codegen/bytecodeText/notNullAssertions/assertionForNotNullTypeParam_1_4.kt

@@ -1,4 +1,4 @@
-// !API_VERSION: LATEST
+// !API_VERSION: LATEST_STABLE
 
 fun <T : Any> foo(t: T) = t
 

compiler/testData/codegen/bytecodeText/nullCheckOptimization/multipleExclExcl_1_4.kt

@@ -1,4 +1,4 @@
-// !API_VERSION: LATEST
+// !API_VERSION: LATEST_STABLE
 
 fun test(s: String?): Int {
     s!!

compiler/testData/codegen/bytecodeText/nullCheckOptimization/nullCheckAfterExclExcl_1_4.kt

@@ -1,4 +1,4 @@
-// !API_VERSION: LATEST
+// !API_VERSION: LATEST_STABLE
 
 fun test(s: String?): Int {
     s!!

compiler/testData/codegen/bytecodeText/nullCheckOptimization/redundantSafeCall_1_4.kt

@@ -1,8 +1,8 @@
-// !API_VERSION: LATEST
+// !API_VERSION: LATEST_STABLE
 
 fun test(s: String) = s?.length
 
 // 0 IFNULL
 // 0 IFNONNULL
 // 0 intValue
-// 1 valueOf
+// 0 valueOf