GH-481: Fix bug where large builds crash on Windows

[ascopes]

This change implements the argument file mechanism for protoc
command line flags, like we do already for Java invocations. This
helps avoid build failures on Windows when a large number of files
are being generated, since Windows has somewhat esoteric limits
on the command line length. Offloading this to a file works around
this constraint.

A reproduction of the issue for Windows is also included in the test
pack, which generates a large number of random protobuf sources on
each build and feeds them into the Maven plugin.

A fix for Mockito has also been included in this change to squelch
warnings about agent attachments that I was encountering on Java 21
builds.

Fixes GH-481.

[codecov]

Codecov Report

Attention: Patch coverage is 92.96875% with 9 lines in your changes missing coverage. Please review.

Project coverage is 87.54%. Comparing base (3c510be) to head (88572e9).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
...protobufmavenplugin/plugins/JvmPluginResolver.java	84.45%	7 Missing ⚠️
...enplugin/generation/ProtobufBuildOrchestrator.java	94.45%	0 Missing and 1 partial ⚠️
...lugin/protoc/ProtocArgumentFileBuilderBuilder.java	96.56%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #482      +/-   ##
==========================================
+ Coverage   87.31%   87.54%   +0.24%     
==========================================
  Files          37       38       +1     
  Lines        1252     1276      +24     
  Branches       92       91       -1     
==========================================
+ Hits         1093     1117      +24     
  Misses        119      119              
  Partials       40       40              

Files with missing lines	Coverage Δ
...rotobufmavenplugin/protoc/CommandLineExecutor.java	78.73% <100.00%> (+3.12%)	⬆️
...protobufmavenplugin/utils/ArgumentFileBuilder.java	100.00% <100.00%> (ø)
...b/ascopes/protobufmavenplugin/utils/TeeWriter.java	100.00% <100.00%> (ø)
...enplugin/generation/ProtobufBuildOrchestrator.java	83.00% <94.45%> (+0.18%)	⬆️
...lugin/protoc/ProtocArgumentFileBuilderBuilder.java	92.60% <96.56%> (ø)
...protobufmavenplugin/plugins/JvmPluginResolver.java	82.90% <84.45%> (+0.35%)	⬆️

[ascopes]

...and with that, we learn that GitHub's auto merge feature is buggy and will merge without waiting for builds to succeed.

Sigh. Any further fixes will have to be done on a new PR.