Build of Client VM is broken after JDK-8307058

* For target hotspot_variant-client_libjvm_objs_zBarrierSetAssembler_x86.o:
/data/jdk/src/hotspot/cpu/x86/gc/z/zBarrierSetAssembler_x86.cpp: In function 'bool is_c2_compilation()':
/data/jdk/src/hotspot/cpu/x86/gc/z/zBarrierSetAssembler_x86.cpp:367:47: error: invalid use of incomplete type 'class CompileTask'
  367 | return task != nullptr && is_c2_compile(task->comp_level());
      | ^~
In file included from /data/jdk/src/hotspot/share/code/codeCache.hpp:29,
                 from /data/jdk/src/hotspot/share/gc/z/zBarrier.inline.hpp:29,
                 from /data/jdk/src/hotspot/cpu/x86/gc/z/zBarrierSetAssembler_x86.cpp:29:
/data/jdk/src/hotspot/share/code/nmethod.hpp:30:7: note: forward declaration of 'class CompileTask'
   30 | class CompileTask;
      | ^~~~~~~~~~~
/data/jdk/src/hotspot/cpu/x86/gc/z/zBarrierSetAssembler_x86.cpp: At global scope:
/data/jdk/src/hotspot/cpu/x86/gc/z/zBarrierSetAssembler_x86.cpp:323:12: error: 'int store_fast_path_check_size(MacroAssembler*, Address, bool, Label&)' defined but not used [-Werror=unused-function]
  323 | static int store_fast_path_check_size(MacroAssembler* masm, Address ref_addr, bool is_atomic, Label& medium_path) {
      | ^~~~~~~~~~~~~~~~~~~~~~~~~~
cc1plus: all warnings being treated as errors

* All command lines available in /data/jdk/build/linux-x86_64-client-fastdebug/make-support/failure-logs.