Use static year range in copyright of generated FIR and tests

Dynamically calculating a year is problematic, especially in cases like
FIR where generation happens in every build. When you are working on a
last year's commit, each build creates a bunch of uncommited
 changes of updating the year in copyrights.

compiler/tests-common/tests/org/jetbrains/kotlin/generators/impl/TestGeneratorImpl.kt

@@ -111,14 +111,9 @@ private class TestGeneratorImplInstance(
         val out = StringBuilder()
         val p = Printer(out)
 
-        val year = GregorianCalendar()[Calendar.YEAR]
-        p.println(
-            """/*
-                | * Copyright 2010-$year JetBrains s.r.o. and Kotlin Programming Language contributors.
-                | * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
-                | */
-                |""".trimMargin()
-        )
+        val copyright = File("license/COPYRIGHT_HEADER.txt").readText()
+        p.println(copyright)
+        p.println()
         p.println("package ", suiteClassPackage, ";")
         p.println()
         p.println("import com.intellij.testFramework.TestDataPath;")