[XLA:GPU] Disable ALL fusion passes in xla_hlo_profile_test.

Rename the "fusion merger" pass to "fusion_merger" such that it can be disabled.
This is in preparation of handling fused and unfused ops more consistently.

PiperOrigin-RevId: 253969358

tensorflow/compiler/xla/service/gpu/fusion_merger.h

@@ -34,7 +34,7 @@ namespace gpu {
 //
 class FusionMerger : public HloModulePass {
  public:
-  absl::string_view name() const override { return "fusion merger"; }
+  absl::string_view name() const override { return "fusion_merger"; }
 
   StatusOr<bool> Run(HloModule* module) override;
 };

tensorflow/compiler/xla/tests/xla_hlo_profile_test.cc

@@ -376,7 +376,8 @@ static std::pair<int, char**> AddXlaHloProfileFlag(int argc, char** argv) {
   // pass, otherwise a while loop is transformed and we could not match the
   // original name in the ProfileWhileComputation test.
   new_argv[argc + 1] = strdup(
-      "--xla_disable_hlo_passes=fusion,while-loop-invariant-code-motion");
+      "--xla_disable_hlo_passes=fusion,fusion_merger,multi_output_fusion,"
+      "while-loop-invariant-code-motion");
   return {argc + 2, new_argv};
 }