Bug: ZGC does not support NMT

[Aleksey Shipilev]

Trying to run ZGC with NMT support, and there is no "Java Heap" section. I guess mtJavaHeap tag is
missing in heap allocation code within ZGC.

$ java -XX:+UseZGC -Xms8g -Xmx8g -XX:NativeMemoryTracking=summary Hello

$ jcmd 57529 VM.native_memory

Total: reserved=310485KB, committed=66769KB
-                     Class (reserved=8303KB, committed=4463KB)
                            (classes #461)
                            (malloc=111KB #603)
                            (mmap: reserved=8192KB, committed=4352KB)
                            (  Metadata:   )
                            (    reserved=8192KB, committed=4352KB)
                            (    used=3703KB)
                            (    free=649KB)
                            (    waste=0KB =0.00%)

-                    Thread (reserved=34978KB, committed=34978KB)
                            (thread #35)
                            (stack: reserved=34892KB, committed=34892KB)
                            (malloc=47KB #187)
                            (arena=40KB #56)

-                      Code (reserved=247726KB, committed=7850KB)
                            (malloc=42KB #474)
                            (mmap: reserved=247684KB, committed=7808KB)

-                        GC (reserved=16921KB, committed=16921KB)
                            (malloc=537KB #51)
                            (mmap: reserved=16384KB, committed=16384KB)

-                  Compiler (reserved=149KB, committed=149KB)
                            (malloc=18KB #53)
                            (arena=131KB #15)

-                  Internal (reserved=317KB, committed=317KB)
                            (malloc=285KB #1058)
                            (mmap: reserved=32KB, committed=32KB)

-                    Symbol (reserved=1727KB, committed=1727KB)
                            (malloc=1111KB #1051)
                            (arena=616KB #1)

-    Native Memory Tracking (reserved=89KB, committed=89KB)
                            (malloc=5KB #56)
                            (tracking overhead=84KB)

-               Arena Chunk (reserved=185KB, committed=185KB)
                            (malloc=185KB)

-                   Logging (reserved=8KB, committed=8KB)
                            (malloc=8KB #158)

-                 Arguments (reserved=17KB, committed=17KB)
                            (malloc=17KB #463)

-                    Module (reserved=57KB, committed=57KB)
                            (malloc=57KB #1129)

-                   Unknown (reserved=8KB, committed=8KB)
                            (mmap: reserved=8KB, committed=8KB)

Thanks,
-Aleksey