[Tests] Add spec tests in FIR + LightTree configuration

In some tests PSI and LT differ. Test data was fixed accordingly.

In the following tests I consider that difference is acceptable:
- compiler/tests-spec/testData/diagnostics/linked/expressions/try-expression/p-1/neg/3.1.kt
- compiler/tests-spec/testData/diagnostics/linked/expressions/try-expression/p-1/neg/4.1.kt

This is because:
- It only happens when recovering from syntax errors happened above in
code. I was unable to reproduce it in valid code.
- It doesn't break parsing further, the rest of the errors in file are
reported identically.

The rest of the tests will be fixed in subsequent commits.

^KT-62704 Fixed

compiler/tests-spec/tests/org/jetbrains/kotlin/spec/utils/tasks/GenerateSpecTests.kt

@@ -15,6 +15,7 @@ import org.jetbrains.kotlin.spec.utils.GeneralConfiguration.SPEC_TEST_PATH
 import org.jetbrains.kotlin.spec.utils.GeneralConfiguration.TESTS_MAP_FILENAME
 import org.jetbrains.kotlin.spec.utils.SectionsJsonMapGenerator
 import org.jetbrains.kotlin.spec.utils.TestsJsonMapGenerator
+import org.jetbrains.kotlin.test.runners.AbstractFirLightTreeDiagnosticTestSpec
 import org.jetbrains.kotlin.test.runners.AbstractFirPsiDiagnosticTestSpec
 import org.jetbrains.kotlin.test.utils.CUSTOM_TEST_DATA_EXTENSION_PATTERN
 import java.io.File
@@ -72,6 +73,13 @@ fun generateTests() {
                     excludedPattern = CUSTOM_TEST_DATA_EXTENSION_PATTERN
                 )
             }
+            testClass<AbstractFirLightTreeDiagnosticTestSpec> {
+                model(
+                    "diagnostics",
+                    excludeDirs = listOf("helpers") + detectDirsWithTestsMapFileOnly("diagnostics"),
+                    excludedPattern = CUSTOM_TEST_DATA_EXTENSION_PATTERN
+                )
+            }
         }
     }
 }