compiler: don't report runtime escapes if we've seen errors

    
    If we get errors during compilation, we skip the escape analysis pass.
    If we are compiling the runtime package, we report an error if a bound
    method expression escapes.  The effect is that if we get an error
    while compiling the runtime package, we would report confusing and
    meaningless errors about bound method expressions escaping.
    
    This CL stops doing that.
    
    Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/192720

From-SVN: r275238

gcc/go/gofrontend/MERGE

-2444eb1e8c697531f8beb403679e4ab00b16dbf5
+80403eb9e95c9642ebabb4d7c43deedaa763211f
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

gcc/go/gofrontend/expressions.cc

@@ -7948,7 +7948,9 @@ Bound_method_expression::do_flatten(Gogo* gogo, Named_object*,
   Node* n = Node::make_node(this);
   if ((n->encoding() & ESCAPE_MASK) == Node::ESCAPE_NONE)
     ret->heap_expression()->set_allocate_on_stack();
-  else if (gogo->compiling_runtime() && gogo->package_name() == "runtime")
+  else if (gogo->compiling_runtime()
+	   && gogo->package_name() == "runtime"
+	   && !saw_errors())
     go_error_at(loc, "%s escapes to heap, not allowed in runtime",
                 n->ast_format(gogo).c_str());