RFR: JDK-8170184 Remove incorrect comments about generated jvmt.h

[Magnus Ihse Bursie]

The inclusion of the generated jvmti.h was fixed in JDK-8063154, however 
the comments still state that this does not work.

Bug: https://bugs.openjdk.java.net/browse/JDK-8170184
Patch inline:
diff --git a/make/gensrc/GensrcJvmti.gmk b/make/gensrc/GensrcJvmti.gmk
--- a/make/gensrc/GensrcJvmti.gmk
+++ b/make/gensrc/GensrcJvmti.gmk
@@ -130,8 +130,6 @@
  TARGETS += $(JVMTI_OUTPUTDIR)/jvmtiEnvRecommended.cpp

  ################################################################################
-# Disable copy of jvmti.h from hotspot until this has been cleared up. 
The file
-# is currently being copied from the jdk repository. See JDK-8167078.
  # Copy jvmti.h to include dir

  # The file is the same regardless of jvm variant. Only let one do the 
copy.

/Magnus