gitlab-ci, build/windows: Move back split of 32-bit symbols to gimp job

Following 0199faac

We use arm64 runners for the installer job to avoid queues, but...
llvm-objcopy is well know to lack parity and one sympthom is the
'invalid SymbolTableIndex' warning when handling x86 debug symbols.

.gitlab-ci.yml

@@ -593,6 +593,7 @@ gimp-win-x86:
   script:
     - C:\msys64\usr\bin\bash -lc "bash -x ./build/windows/gitlab-ci/2_build-gimp-msys2.sh"
     - C:\msys64\usr\bin\bash -lc "bash -x ./build/windows/gitlab-ci/3_bundle-gimp-uni_base.sh"
+    - C:\msys64\usr\bin\bash -lc "bash -x build/windows/gitlab-ci/3_bundle-gimp-uni_sym.sh"
   artifacts:
     paths:
       - gimp-x86/

build/windows/gitlab-ci/3_bundle-gimp-uni_sym.sh

@@ -1,8 +1,11 @@
 #!/bin/bash
 
-archsArray=("-a64"
-            "-x64"
-            "-x86")
+if [ "$MSYSTEM_CARCH" != 'i686' ]; then
+  archsArray=('-a64'
+              '-x64')
+else
+  archsArray=('-x86')
+fi
 
 # Splited .debug (DWARF) debug symbols
 # (we extract and link them to make possible save space with Inno custom install)