KotlinCliJavaFileManagerImpl: don't cache empty search result

The result wasn't cached if findVirtualFileForTopLevelClass failed prior
to 23e5f77ff, which makes the empty list cached. AnalysisHandlers like
KSP rely on the previous behavior to introduce new Java files in
repeated analyses.

This patch reverts to the old behavior with minimal changes.

A better fix might be exposing the ability to let callers of
KotlinCliJavaFileManager invalidate the cache but that would be a larger
change.

compiler/cli/cli-base/src/org/jetbrains/kotlin/cli/jvm/compiler/KotlinCliJavaFileManagerImpl.kt

diff --git a/compiler/cli/cli-base/src/org/jetbrains/kotlin/cli/jvm/compiler/KotlinCliJavaFileManagerImpl.kt b/compiler/cli/cli-base/src/org/jetbrains/kotlin/cli/jvm/compiler/KotlinCliJavaFileManagerImpl.kt
index 30ad47a..a0e377f 100644
--- a/compiler/cli/cli-base/src/org/jetbrains/kotlin/cli/jvm/compiler/KotlinCliJavaFileManagerImpl.kt
+++ b/compiler/cli/cli-base/src/org/jetbrains/kotlin/cli/jvm/compiler/KotlinCliJavaFileManagerImpl.kt
@@ -62,7 +62,7 @@
      * able to find its own correct version of the globally ambiguous class. But since [topLevelClassesCache] is global as well and not tied
      * to a specific module or scope, we need to cache that global view.
      */
-    private val topLevelClassesCache: MutableMap<FqName, SmartList<VirtualFile>> = Object2ObjectOpenHashMap()
+    private val topLevelClassesCache: MutableMap<FqName, SmartList<VirtualFile>?> = Object2ObjectOpenHashMap()
 
     private val allScope = GlobalSearchScope.allScope(myPsiManager.project)
     private var usePsiClassFilesReading = false
@@ -106,8 +106,8 @@
                     index.findClasses(outerMostClassId) { dir, type ->
                         findVirtualFileGivenPackage(dir, relativeClassName, type)
                     }
-                )
-        }.firstOrNull { it in searchScope }
+                ).takeIf { it.isNotEmpty() }
+        }?.firstOrNull { it in searchScope }
     }
 
     private val binaryCache: MutableMap<ClassId, JavaClass?> = Object2ObjectOpenHashMap()