Fix compileMixed test

Author: smarter

compiler/test/dotc/tests.scala

@@ -224,7 +224,7 @@ class tests extends CompilerTest {
         |../scala2-library/src/library/scala/package.scala
         |../scala2-library/src/library/scala/collection/GenSeqLike.scala
         |../scala2-library/src/library/scala/collection/SeqLike.scala
-        |../scala2-library/src/library/scala/collection/generic/GenSeqFactory.scala""".stripMargin)
+        |../scala2-library/src/library/scala/collection/generic/GenSeqFactory.scala""".stripMargin)(scala2mode ++ defaultOptions)
   @Test def compileIndexedSeq = compileLine("../scala2-library/src/library/scala/collection/immutable/IndexedSeq.scala")
   @Test def compileParSetLike = compileLine("../scala2-library/src/library/scala/collection/parallel/mutable/ParSetLike.scala")
   @Test def compileParSetSubset = compileLine(

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

@@ -57,7 +57,7 @@ class CompilationTests extends ParallelTesting {
         "../scala2-library/src/library/scala/collection/SeqLike.scala",
         "../scala2-library/src/library/scala/collection/generic/GenSeqFactory.scala"
       ),
-      defaultOptions
+      scala2Mode
     ) +
     compileFilesInDir("../tests/pos-special/spec-t5545", defaultOptions) +
     compileFilesInDir("../tests/pos-special/strawman-collections", defaultOptions) +