Windows reproducible build & ccache hit rate improvement

[amd-nicknick]

Motivation

Fixes #4519, parent issue #4195

Technical Details

• Reproducible builds on Windows via /Brepro for MSVC toolchain
  Ensure amd-llvm is reproducible & COFF header contains a reproducible hash instead of current timestamp.
• compiler_check=content for Windows
  Switch compiler_check from mtime to content. Since the LLVM toolchain on Windows is statically linked, hashing the compiler binary content is sufficient and more reliable for detecting actual compiler changes across CI runs.
• Support PCH
  Add pch_defines and time_micros to ccache sloppiness. amd-llvm on Windows builds uses precompiled headers by default.
• Misc changes to ccache config
  Max size bump to 10G, rename secondary_storage to remote_storage

Test Plan

Validate cache hitrate on Windows following subsequent buil.ds

Test Result

(therock-build-venv) D:\Nick\TheRock\TheRock>ccache -s -v
Cache directory:                D:\Nick\TheRock\TheRock\.ccache\local
Config file:                    D:\Nick\TheRock\TheRock\.ccache\ccache.conf
System config file:
Stats updated:                  04/17/26 05:11:03
Cacheable calls:                28464 /  30423 (93.56%)
  Hits:                         28128 /  28464 (98.82%)
    Direct:                     28128 /  28128 (100.0%)
    Preprocessed:                   0 /  28128 ( 0.00%)
  Misses:                         336 /  28464 ( 1.18%)
Uncacheable calls:               1959 /  30423 ( 6.44%)
  Compilation failed:              13 /   1959 ( 0.66%)
  Compiler output file missing:  1149 /   1959 (58.65%)
  No input file:                  371 /   1959 (18.94%)
  Preprocessing failed:            69 /   1959 ( 3.52%)
  Unsupported code directive:       3 /   1959 ( 0.15%)
  Unsupported compiler option:    354 /   1959 (18.07%)
Successful lookups:
  Direct:                       28128 /  29698 (94.71%)
  Preprocessed:                     0 /   1498 ( 0.00%)
Local storage:
  Cache size (GB):                7.2 / 1024.0 ( 0.70%)
  Files:                        68376
  Hits:                         28128 /  28464 (98.82%)
  Misses:                         336 /  28464 ( 1.18%)
  Reads:                        59324
  Writes:                         672

Submission Checklist

• Look over the contributing guidelines at https://github.com/ROCm/ROCm/blob/develop/CONTRIBUTING.md#pull-requests.