Do not put blaze-grepped_includes_<lang> files inside tree artifact d…

…irectories

RELNOTES: None.
PiperOrigin-RevId: 266890605

src/main/java/com/google/devtools/build/lib/includescanning/SpawnIncludeScanner.java

@@ -283,8 +283,9 @@ public Collection<Inclusion> extractInclusions(
       ActionExecutionContext actionExecutionContext,
       Artifact grepIncludes,
       GrepIncludesFileType fileType,
-      boolean placeNextToFile)
+      boolean isOutputFile)
       throws IOException, ExecException, InterruptedException {
+    boolean placeNextToFile = isOutputFile && !file.hasParent();
     Path output = getIncludesOutput(file, actionExecutionContext.getPathResolver(), fileType,
         placeNextToFile);
     if (!inMemoryOutput) {