hg: loom/loom: Test single stepping into Continuation.doContinue()

[chris.plummer at oracle.com]

Changeset: 5c2e1eac112b
Author:    cjplummer
Date:      2019-06-09 22:46 -0700
URL:       http://hg.openjdk.java.net/loom/loom/rev/5c2e1eac112b

Test single stepping into Continuation.doContinue()

+ test/hotspot/jtreg/serviceability/jvmti/DoContinueSingleStepTest/DoContinueSingleStepTest.java
+ test/hotspot/jtreg/serviceability/jvmti/DoContinueSingleStepTest/libDoContinueSingleStepTest.cpp