Minor cleanups in Skylark

--
MOS_MIGRATED_REVID=87535290
diff --git a/src/test/java/com/google/devtools/build/lib/syntax/ParserTest.java b/src/test/java/com/google/devtools/build/lib/syntax/ParserTest.java
index a4fa5d1..9a407d2 100644
--- a/src/test/java/com/google/devtools/build/lib/syntax/ParserTest.java
+++ b/src/test/java/com/google/devtools/build/lib/syntax/ParserTest.java
@@ -292,7 +292,7 @@
     String expr = "f(1 % 2)";
     FuncallExpression call = (FuncallExpression) parseExpr(expr);
     Argument.Passed arg = call.getArguments().get(0);
-    assertTrue(arg.getLocation().getEndOffset() < call.getLocation().getEndOffset());
+    assertThat(arg.getLocation().getEndOffset()).isLessThan(call.getLocation().getEndOffset());
   }
 
   @Test
@@ -300,7 +300,7 @@
     String expr = "f(1 + 2)";
     FuncallExpression call = (FuncallExpression) parseExpr(expr);
     Argument.Passed arg = call.getArguments().get(0);
-    assertTrue(arg.getLocation().getEndOffset() < call.getLocation().getEndOffset());
+    assertThat(arg.getLocation().getEndOffset()).isLessThan(call.getLocation().getEndOffset());
   }
 
   @Test