Fix unmangling of satellite assembly names

Fixes: #9532
Context: 86260ed

All the assemblies are wrapped in a valid ELF shared library image and
placed in the `lib/{ABI}` directories inside the APK/AAB archive.  Since
those directories don't support subdirectories, we need to encode
satellite assembly culture in a way that doesn't use the `/` directory
separator char.  This encoding, as originally implemented, unfortunately
used the `-` character which made it ambiguous with culture names that
consist of two parts (e.g. `de-DE`), since the unmangling process would
look for the first occurrence of `-` to replace it with `/`, which would
form invalid assembly names such as `de/DE-MyAssembly.resources.dll`
instead of the correct `de-DE/MyAssembly.resources.dll`.  This would,
eventually, lead to a mismatch when looking for satellite assembly for
that specific culture.

Fix it by changing the `-` character to `_` so that mangled assembly
name looks like `lib_de-DE_MyAssembly.resources.dll.so` and we can
unambiguously decode it to the correct `de-DE/MyAssembly.resources.dll`
name.

src/Xamarin.Android.Build.Tasks/Utilities/MonoAndroidHelper.Basic.cs

@@ -208,7 +208,7 @@ public static string MakeZipArchivePath (string part1, ICollection<string>? path
 	public static string MakeDiscreteAssembliesEntryName (string name, string? culture = null)
 	{
 		if (!String.IsNullOrEmpty (culture)) {
-			return $"{MANGLED_ASSEMBLY_SATELLITE_ASSEMBLY_MARKER}{culture}-{name}{MANGLED_ASSEMBLY_NAME_EXT}";
+			return $"{MANGLED_ASSEMBLY_SATELLITE_ASSEMBLY_MARKER}{culture}_{name}{MANGLED_ASSEMBLY_NAME_EXT}";
 		}
 
 		return $"{MANGLED_ASSEMBLY_REGULAR_ASSEMBLY_MARKER}{name}{MANGLED_ASSEMBLY_NAME_EXT}";

src/native/monodroid/embedded-assemblies.hh

@@ -405,7 +405,7 @@ namespace xamarin::android::internal {
 			if constexpr (IsSatelliteAssembly) {
 				// Make sure assembly name is {CULTURE}/assembly.dll
 				for (size_t idx = start_idx; idx < name.length (); idx++) {
-					if (name[idx] == SharedConstants::SATELLITE_ASSEMBLY_MARKER_CHAR) {
+					if (name[idx] == SharedConstants::SATELLITE_CULTURE_END_MARKER_CHAR) {
 						name[idx] = '/';
 						break;
 					}

src/native/runtime-base/shared-constants.hh

@@ -27,6 +27,7 @@ namespace xamarin::android::internal
 		static constexpr std::string_view MANGLED_ASSEMBLY_SATELLITE_ASSEMBLY_MARKER { "lib-" };
 		static constexpr size_t SATELLITE_ASSEMBLY_MARKER_INDEX = 3uz;            // this ☝️
 		static constexpr char SATELLITE_ASSEMBLY_MARKER_CHAR = MANGLED_ASSEMBLY_SATELLITE_ASSEMBLY_MARKER[SATELLITE_ASSEMBLY_MARKER_INDEX];
+		static constexpr char SATELLITE_CULTURE_END_MARKER_CHAR = '_';
 
 		static constexpr std::string_view MONO_ANDROID_RUNTIME_ASSEMBLY_NAME  { "Mono.Android.Runtime" };
 		static constexpr std::string_view MONO_ANDROID_ASSEMBLY_NAME          { "Mono.Android" };