fix test group

Author: liufengyun

compiler/test/dotty/tools/dotc/CompilationTests.scala

@@ -106,7 +106,6 @@ class CompilationTests extends ParallelTesting {
     compileFilesInDir("tests/pos-deep-subtype", allowDeepSubtypes) +
     compileFilesInDir("tests/pos-kind-polymorphism", defaultOptions and "-Ykind-polymorphism") +
     compileDir("tests/pos/i1137-1", defaultOptions and "-Yemit-tasty") +
-    compileDir("tests/neg-custom-args/isInstanceOf", defaultOptions and "-Xfatal-warnings") +
     compileFile(
       // succeeds despite -Xfatal-warnings because of -nowarn
       "tests/neg-custom-args/fatal-warnings/xfatalWarnings.scala",
@@ -191,6 +190,7 @@ class CompilationTests extends ParallelTesting {
     compileFile("tests/neg-custom-args/noimports2.scala", defaultOptions.and("-Yno-imports")) +
     compileFile("tests/neg-custom-args/i3882.scala", allowDeepSubtypes) +
     compileFile("tests/neg-custom-args/i1754.scala", allowDeepSubtypes) +
+    compileDir("tests/neg-custom-args/isInstanceOf", defaultOptions and "-Xfatal-warnings") +
     compileFile("tests/neg-custom-args/i3627.scala", allowDeepSubtypes)
   }.checkExpectedErrors()