fix two psi elements per one ast element in stub-ast switch:

psi1 is taken from stub
  psi2 is eagerly created during chameleon parsing
  another thread gets the ast when some psi1 parent is already switched and psi1 is not, it walks down the ast and gets psi2

java/java-tests/testSrc/com/intellij/psi/StubAstSwitchTest.groovy

@@ -66,7 +66,9 @@ class StubAstSwitchTest extends LightCodeInsightFixtureTestCase {
     int count = 100
     List<PsiClass> classList = (0..<count).collect {
       myFixture.addClass("class Foo$it { " +
-                         (0..<100).collect { "void foo$it(int i, boolean b, Object o) {}" }.join("\n") +
+                         "void foo$it(" +
+                         (0..250).collect { "int i$it"}.join(", ") +
+                         ") {}" +
                          " }")
     }
     CountDownLatch latch = new CountDownLatch(count)