Fix test by using private_key parameter.

runtime/vm/debugger_test.cc

Index: runtime/vm/debugger_test.cc
diff --git a/runtime/vm/debugger_test.cc b/runtime/vm/debugger_test.cc
index c715c3df2fd1d2512baec61190725c349a2127c8..8963195085e74d01175739853ea99276dd2cade9 100644
--- a/runtime/vm/debugger_test.cc
+++ b/runtime/vm/debugger_test.cc
@@ -155,13 +155,13 @@ TEST_CASE(Debugger_PrintBreakpointsToJSONArray) {
         "[{\"type\":\"Breakpoint\",\"fixedId\":true,\"id\":\"breakpoints\\/"
         "2\",\"breakpointNumber\":2,\"resolved\":false,\"location\":{\"type\":"
         "\"UnresolvedSourceLocation\",\"script\":{\"type\":\"@Script\","
-        "\"fixedId\":true,\"id\":\"libraries\\/@15247669\\/scripts\\/"
+        "\"fixedId\":true,\"id\":\"libraries\\/%s\\/scripts\\/"
         "test-lib\\/"
         "0\",\"uri\":\"test-lib\",\"_kind\":\"script\"},\"line\":3}},{\"type\":"
         "\"Breakpoint\",\"fixedId\":true,\"id\":\"breakpoints\\/"
         "1\",\"breakpointNumber\":1,\"resolved\":false,\"location\":{\"type\":"
         "\"UnresolvedSourceLocation\",\"script\":{\"type\":\"@Script\","
-        "\"fixedId\":true,\"id\":\"libraries\\/@15247669\\/scripts\\/"
+        "\"fixedId\":true,\"id\":\"libraries\\/%s\\/scripts\\/"
         "test-lib\\/"
         "0\",\"uri\":\"test-lib\",\"_kind\":\"script\"},\"line\":2}},{\"type\":"
         "\"Breakpoint\",\"fixedId\":true,\"id\":\"breakpoints\\/"