Add debugger protocol request for setting global flags.

test/mjsunit/debug-enable-disable-breakpoints.js

Index: test/mjsunit/debug-enable-disable-breakpoints.js
diff --git a/test/mjsunit/debug-enable-disable-breakpoints.js b/test/mjsunit/debug-enable-disable-breakpoints.js
index 071397beacaed58091d7dfc5a66afa9812fd2a0d..4592ffcc2eda25bf611a6b6ded99dd01a47a26c7 100644
--- a/test/mjsunit/debug-enable-disable-breakpoints.js
+++ b/test/mjsunit/debug-enable-disable-breakpoints.js
@@ -88,3 +88,18 @@ assertEquals(5, break_point_hit_count);
 Debug.disableBreakPoint(bp1);
 f();
 assertEquals(6, break_point_hit_count);
+
+// Deactivate all breakpoints.
+Debug.debuggerFlags().breakPointsActive.setValue(false);
+f();
+assertEquals(6, break_point_hit_count);
+
+// Enable the first breakpoint.
+Debug.enableBreakPoint(bp1);
+f();
+assertEquals(6, break_point_hit_count);
+
+// Activate all breakpoints.
+Debug.debuggerFlags().breakPointsActive.setValue(true);
+f();
+assertEquals(7, break_point_hit_count);