[CI] Reduce Windows debug binary size

This resolves CI failures due to running out of disk space, at least for
the near term. Also drops a flag modifying features for windows_no_dbg,
disabling optimizations when building for the host configuration is not
necessary.

.bazelrc

@@ -207,9 +207,14 @@ build:windows_no_dbg -c opt
 build:windows_no_dbg --copt='-O0' --host_copt='-O0'
 build:windows_no_dbg --copt='/Od' --host_copt='/Od'
 build:windows_no_dbg --copt='/INCREMENTAL:NO' --host_copt='/INCREMENTAL:NO'
-build:windows_no_dbg --noincompatible_use_host_features
 build:windows_no_dbg --features=-smaller_binary --features=-disable_assertions_feature
 
+# Mitigate the large size impact of Windows debug binaries somewhat by applying string merging and
+# linker garbage collection.
+build:windows_dbg --config=debug
+build:windows_dbg --copt='/Gy' --copt='/Gw' --copt='/GF'
+build:windows_dbg --linkopt='/OPT:REF'
+
 build:windows --cxxopt='/std:c++20' --host_cxxopt='/std:c++20'
 build:windows --cxxopt='/await' --host_cxxopt='/await'
 build:windows --copt='/D_CRT_USE_BUILTIN_OFFSETOF' --host_copt='/D_CRT_USE_BUILTIN_OFFSETOF'

.github/workflows/test.yml

@@ -32,10 +32,14 @@ jobs:
           # Windows has a custom non-debug bazel config.
           - os:     { name : windows, image : windows-2022 }
             config: { suffix: '', bazel-args: --config=windows_no_dbg }
+          - os:     { name : windows, image : windows-2022 }
+            config: { suffix: -debug, bazel-args: --config=windows_dbg }
         exclude:
           # Skip the matrix generated Windows non-debug config to use the one added above.
           - os:     { name : windows, image : windows-2022 }
             config: { suffix: '', bazel-args: '' }
+          - os:     { name : windows, image : windows-2022 }
+            config: { suffix: -debug, bazel-args: --config=debug }
       fail-fast: false
     runs-on: ${{ matrix.os.image }}
     name: test (${{ matrix.os.name }}${{ matrix.config.suffix }})