8201542: Remove unused _gc_timer field in GCMemoryManager Summary: Minor cleanup to remove unused field Reviewed-by: shade, minqi

8200167: Validate more special case invocations Reviewed-by: acorn, vlivanov, dholmes Contributed-by: John Rose <john.rose@oracle.com>, Vladimir Ivanov <vladimir.x.ivanov@oracle.com>, Tobias Hartmann <tobias.hartmann@oracle.com>

8199643: [TESTBUG] Open source common VM testbase code Reviewed-by: vlivanov, erikj, mseledtsov, gthornbr

8202399: [C1] LIRGenerator::do_CheckCast needs to exclude is_invokespecial_receiver_check() when using PatchAlot Reviewed-by: kvn Contributed-by: Vladimir Ivanov <vladimir.x.ivanov@oracle.com>

8202452: Delete test files missed from commit for 8193213&8182731. Summary: Deleted outdated tests. Reviewed-by: dholmes

8193213: Make the UseAppCDS option obsolete. 8182731: Odd handling of -XX:-UseAppCDS and -XX:SharedArchiveFile. Summary: Application class data sharing is enabled without -XX:+UseAppCDS. SharedArchiveFile is now a product flag. Reviewed-by: dholmes, ihse, erikj, ccheung

8202284: FileChannel and FileOutpuStream variants of AtomicAppend should fail silently on macOS >= 10.13 Reviewed-by: chegar

8202381: (Solaris) SIGBUS in # V [libjvm.so+0xcee494] jni_GetIntField+0x224 Reviewed-by: kbarrett, dcubed

8202383: Custom extensions for jvmti doc Reviewed-by: erikj Contributed-by: archana.nogriya@uk.ibm.com

8154204: [TESTBUG] Update DefaultUseWithClient test to handle client-less builds Summary: removed the DefaultUseWithClient.java test Reviewed-by: hseigel, jiangli