Initialize coverage object at the beginning of the script.

The coverage object needs to be initialized before any code gets
executed; @JsType exports may require execution of clinits during
setup and fail when coverage is enabled if the coverage object is
not yet initialized.

Change-Id: Ia00a9b8d77e22f21c297f41ac52ddd386e2fced2
diff --git a/dev/core/src/com/google/gwt/dev/js/CoverageInstrumentor.java b/dev/core/src/com/google/gwt/dev/js/CoverageInstrumentor.java
index 9c7db5d..ca7f0f9 100644
--- a/dev/core/src/com/google/gwt/dev/js/CoverageInstrumentor.java
+++ b/dev/core/src/com/google/gwt/dev/js/CoverageInstrumentor.java
@@ -151,6 +151,6 @@
     JsNameRef coverageObject = coverageFieldName.makeRef(info);
     JsBinaryOperation init = new JsBinaryOperation(info, JsBinaryOperator.ASG, coverageObject,
         baselineCoverage(info, instrumentableLines));
-    jsProgram.getGlobalBlock().getStatements().add(init.makeStmt());
+    jsProgram.getGlobalBlock().getStatements().add(0, init.makeStmt());
   }
 }
\ No newline at end of file