[Single-exe] A few small updates

Make a few small improvements to the single-file bundle handling code.
Implements changes suggested by @janvorli in dotnet#26504

src/binder/assemblybinder.cpp

@@ -645,7 +645,6 @@ namespace BINDER_SPACE
         _ASSERTE(ppSystemAssembly != NULL);
 
         ReleaseHolder<Assembly> pSystemAssembly;
-        StackSString sCoreLib;
 
         // For normal runs, corelib is expected to be found in systemDirectory.
         // For self-contained single-file bundles, corelib is expected within the bundle
@@ -657,7 +656,7 @@ namespace BINDER_SPACE
             sCoreLibDir.Append(DIRECTORY_SEPARATOR_CHAR_W);
         }
 
-        sCoreLib = sCoreLibDir;
+        StackSString sCoreLib(sCoreLibDir);
         sCoreLib.Append(CoreLibName_IL_W);
 
         // At run-time, System.Private.CoreLib.dll is expected to be the NI image.

src/coreclr/hosts/unixcorebundle/bundle/runner.cpp

@@ -35,7 +35,7 @@ bool runner_t::probe(const char *relative_path, int64_t *size, int64_t *offset)
 {
     for (file_entry_t& entry : m_manifest.files)
     {
-        if (strcmp(entry.relative_path().c_str(), relative_path) == 0)
+        if(entry.relative_path() == relative_path)
         {
             *size = entry.size();
             *offset = entry.offset();

src/dlls/mscoree/unixinterface.cpp

@@ -135,6 +135,10 @@ static void ConvertConfigPropertiesToUnicode(
             // If this application is a single-file bundle, the bundle-probe callback 
             // is passed in as the value of "BUNDLE_PROBE" property (masquarading as char *).
             // Therefore obtain the value; don't convert it to Unicode.
+            //
+            // This method of communicating "BUNDLE_PROBE" as a string is a temporary hack.
+            // Please see https://github.com/dotnet/coreclr/issues/26752 about 
+            // designing a better corehost-coreclr interface.
 
             *bundleProbe = (BundleProbe *)propertyValues[propertyIndex];
             propertyKeysW[propertyIndex] = W("BUNDLE_PROBE");
@@ -175,7 +179,6 @@ extern "C" int coreclr_create_delegate(void*, unsigned int, const char*, const c
 // Returns:
 //  HRESULT indicating status of the operation. S_OK if the assembly was successfully executed
 //
-
 extern "C"
 DLLEXPORT
 int coreclr_initialize(