[8u40] Bulk backport request: 8040798, 8042570, 8042428, 8043158

[Albert Noll]

Hi,

please review this request to backport the following fixes. These 
patches fix JDK-8055420, which appears only in 8u, and not in 9. I 
tested the 8u version and the bug is not reproducible anymore.

(1)
https://bugs.openjdk.java.net/browse/JDK-8040798
http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/48c15b47a4f1
Unfortunately, this changeset does not apply cleanly due to the changes 
of JDK-8025856. I resolved this conflict manually, since backporting 
JDK-8025856 results in other conflicts. The mercurial output is:

@@ -387,7 +387,7 @@
  void SimpleThresholdPolicy::method_back_branch_event(methodHandle mh, 
methodHandle imh,
                                                       int bci, 
CompLevel level, nmethod* nm, JavaThread* thread) {
    // If the method is already compiling, quickly bail out.
-  if (is_compilation_enabled() && 
!CompileBroker::compilation_is_in_queue(mh, bci)) {
+  if (is_compilation_enabled() && 
!CompileBroker::compilation_is_in_queue(mh)) {
      // Use loop event as an opportunity to also check there's been
      // enough calls.
      CompLevel cur_level = comp_level(mh());

The change in the comment "// Use loop event as an opportunity to also 
check there's been" causes the conflict.

(2)
https://bugs.openjdk.java.net/browse/JDK-8042570
http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/8fddb780f3a7

(3)
https://bugs.openjdk.java.net/browse/JDK-8042428
http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/6786f914240e

(4)
https://bugs.openjdk.java.net/browse/JDK-8043158
http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/98a3a2dea3b9

Thanks,
Albert