RFR: 8309413: General improvements to MethodTypeDesc implementation [v5]

[Chen Liang]

> This patch aims to improve the performance of MethodTypeDesc in general, as it is currently a performance bottleneck in the Classfile API. A previous revision changed the parameter storage from an array to a list; this is dropped now. Sorry for the force push.
> 
> 
> Benchmark                                                             (descString)  Mode  Cnt    Score   Error  Units
> MethodTypeDescFactories.descriptorString   (Ljava/lang/Object;Ljava/lang/String;)I  avgt    6   27.778 ± 0.573  ns/op
> MethodTypeDescFactories.descriptorString                                       ()V  avgt    6   13.343 ± 0.235  ns/op
> MethodTypeDescFactories.descriptorString  ([IJLjava/lang/String;Z)Ljava/util/List;  avgt    6   40.828 ± 0.448  ns/op
> MethodTypeDescFactories.descriptorString                     ()[Ljava/lang/String;  avgt    6   14.754 ± 0.162  ns/op
> MethodTypeDescFactories.ofArray            (Ljava/lang/Object;Ljava/lang/String;)I  avgt    6    8.616 ± 0.132  ns/op
> MethodTypeDescFactories.ofArray                                                ()V  avgt    6    2.146 ± 0.293  ns/op
> MethodTypeDescFactories.ofArray           ([IJLjava/lang/String;Z)Ljava/util/List;  avgt    6   14.595 ± 0.235  ns/op
> MethodTypeDescFactories.ofArray                              ()[Ljava/lang/String;  avgt    6    2.064 ± 0.085  ns/op
> MethodTypeDescFactories.ofDescriptor       (Ljava/lang/Object;Ljava/lang/String;)I  avgt    6   97.077 ± 2.482  ns/op
> MethodTypeDescFactories.ofDescriptor                                           ()V  avgt    6   13.563 ± 0.111  ns/op
> MethodTypeDescFactories.ofDescriptor      ([IJLjava/lang/String;Z)Ljava/util/List;  avgt    6  130.543 ± 2.847  ns/op
> MethodTypeDescFactories.ofDescriptor                         ()[Ljava/lang/String;  avgt    6   35.286 ± 0.260  ns/op
> MethodTypeDescFactories.ofList             (Ljava/lang/Object;Ljava/lang/String;)I  avgt    6    4.156 ± 0.258  ns/op
> MethodTypeDescFactories.ofList                                                 ()V  avgt    6    2.192 ± 0.063  ns/op
> MethodTypeDescFactories.ofList            ([IJLjava/lang/String;Z)Ljava/util/List;  avgt    6   41.002 ± 0.235  ns/op
> MethodTypeDescFactories.ofList                               ()[Ljava/lang/String;  avgt    6    2.200 ± 0.041  ns/op

Chen Liang has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains two commits:

 - Forgot to upload latest micro
 - general optimizations to MTD, no longer change backing storage

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Changes: https://git.openjdk.org/jdk/pull/13186/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13186&range=04
  Stats: 305 lines in 7 files changed: 201 ins; 42 del; 62 mod
  Patch: https://git.openjdk.org/jdk/pull/13186.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13186/head:pull/13186

PR: https://git.openjdk.org/jdk/pull/13186