Avoid creating many distinct suffixes for the atomic writes of action inputs.

PiperOrigin-RevId: 515354520
Change-Id: I0b7fbe964f378c66fe69f9cfabc729718b9811a7

Author: larsrc-google

src/main/java/com/google/devtools/build/lib/sandbox/SandboxHelpers.java

@@ -468,14 +468,17 @@ public SandboxInputs processInputFiles(
       PathFragment pathFragment = e.getKey();
       ActionInput actionInput = e.getValue();
       if (actionInput instanceof VirtualActionInput) {
+        // TODO(larsrc): Figure out which VAIs actually require atomicity, maybe avoid it.
         VirtualActionInput input = (VirtualActionInput) actionInput;
         byte[] digest =
             input.atomicallyWriteRelativeTo(
                 execRootPath,
                 // When 2 actions try to atomically create the same virtual input, they need to have
                 // a different suffix for the temporary file in order to avoid racy write to the
                 // same one.
-                ".sandbox" + tempFileUniquifierForVirtualInputWrites.incrementAndGet());
+                "_sandbox"
+                    + tempFileUniquifierForVirtualInputWrites.incrementAndGet()
+                    + ".virtualinputlock");
         virtualInputs.put(input, digest);
       }