Include compiler flags from system property when interpreting pragma

When interpreting the #partest pragma in check files, also look for
compiler flags that were provided using the partest.scalac_opts system
property. That is, for example, when running

    SCALAC_OPTS="-Ydelambdafy:method" test/partest test/files/...

Author: lrytz

src/main/scala/scala/tools/partest/nest/Runner.scala

@@ -248,7 +248,8 @@ class Runner(val testFile: File, val suiteRunner: SuiteRunner) {
     // use lines in block so labeled? Default to sorry, Charlie.
     def retainOn(expr: String) = {
       val f = expr.trim
-      def flagWasSet(f: String) = suiteRunner.scalacExtraArgs contains f
+      val allArgs = suiteRunner.scalacExtraArgs ++ PartestDefaults.scalacOpts.split(' ')
+      def flagWasSet(f: String) = allArgs contains f
       val (invert, token) =
         if (f startsWith "!") (true, f drop 1) else (false, f)
       val cond = token.trim match {