8369983: Remove expired ZGC flags for JDK 26

Reviewed-by: ayang, aboldtch

Author: jsikstro

src/hotspot/share/runtime/arguments.cpp

@@ -545,8 +545,6 @@ static SpecialFlag const special_jvm_flags[] = {
   { "UseOprofile",                  JDK_Version::jdk(25), JDK_Version::jdk(26), JDK_Version::jdk(27) },
 #endif
   { "MetaspaceReclaimPolicy",       JDK_Version::undefined(), JDK_Version::jdk(21), JDK_Version::undefined() },
-  { "ZGenerational",                JDK_Version::jdk(23), JDK_Version::jdk(24), JDK_Version::undefined() },
-  { "ZMarkStackSpaceLimit",         JDK_Version::undefined(), JDK_Version::jdk(25), JDK_Version::undefined() },
   { "G1UpdateBufferSize",           JDK_Version::undefined(), JDK_Version::jdk(26), JDK_Version::jdk(27) },
   { "ShenandoahPacing",             JDK_Version::jdk(25), JDK_Version::jdk(26), JDK_Version::jdk(27) },
 #if defined(AARCH64)