wip - fix issues with profiler state leaking between specs (StackProf)

sentry-ruby/spec/sentry/rack/capture_exceptions_spec.rb

@@ -681,11 +681,6 @@ def will_be_sampled_by_sdk
 
   shared_examples "a profiled transaction" do
     it "collects a profile" do
-      app = ->(_) do
-        ProfilerTest::Bar.bar
-        [200, {}, "ok"]
-      end
-
       stack = described_class.new(app)
       stack.call(env)
       event = last_sentry_event
@@ -729,11 +724,9 @@ def will_be_sampled_by_sdk
 
   describe "profiling with StackProf", when: :stack_prof_installed? do
     context "when profiling is enabled" do
-      before do
-        perform_basic_setup do |config|
-          config.traces_sample_rate = 1.0
-          config.profiles_sample_rate = 1.0
-          config.release = "test-release"
+      let(:app) do
+         ->(_) do
+          [200, {}, "ok"]
         end
       end
 
@@ -745,7 +738,14 @@ def will_be_sampled_by_sdk
       end
 
       before do
+        perform_basic_setup do |config|
+          config.traces_sample_rate = 1.0
+          config.profiles_sample_rate = 1.0
+          config.release = "test-release"
+        end
+
         StackProf.stop
+
         allow(StackProf).to receive(:results).and_return(stackprof_results)
       end
 
@@ -755,6 +755,13 @@ def will_be_sampled_by_sdk
 
   describe "profiling with vernier", when: :vernier_installed? do
     context "when profiling is enabled" do
+      let(:app) do
+         ->(_) do
+          ProfilerTest::Bar.bar
+          [200, {}, "ok"]
+        end
+      end
+
       before do
         perform_basic_setup do |config|
           config.traces_sample_rate = 1.0