Move JSSyntaxRegExp to core as a private member. This removes the last refrences to dart:coreimpl.

compiler/java/com/google/dart/compiler/CommandLineOptions.java

Index: compiler/java/com/google/dart/compiler/CommandLineOptions.java
diff --git a/compiler/java/com/google/dart/compiler/CommandLineOptions.java b/compiler/java/com/google/dart/compiler/CommandLineOptions.java
index 568c8afafeadcaaedad0f5abeeed836911d70e47..93220fbd3e53264230779071e87b2a9153cb85fb 100644
--- a/compiler/java/com/google/dart/compiler/CommandLineOptions.java
+++ b/compiler/java/com/google/dart/compiler/CommandLineOptions.java
@@ -30,9 +30,6 @@ public class CommandLineOptions {
         usage = "Batch mode (for unit testing)")
     private boolean batch = false;
 
-    @Option(name = "--expose_core_impl", usage = "Automatic import of dart:coreimpl library")
-    private boolean exposeCoreImpl = false;
-
     @Option(name = "--error_format",
         usage = "Format errors as normal or machine")
     private String errorFormat = "";
@@ -125,13 +122,6 @@ public class CommandLineOptions {
     @Argument
     private final List<String> sourceFiles = new ArrayList<String>();
 
-    /**
-     * @return <code>true</code> to automatically import dart:coreimpl
-     */
-    public boolean shouldExposeCoreImpl() {
-      return exposeCoreImpl;
-    }
-
     public String getJvmMetricOptions() {
       if (!showJvmMetrics) {
         return null;