serialize global state tests

Author: kukushechkin

Tests/TracingTests/TracingInstrumentationSystemTests.swift

@@ -33,7 +33,7 @@ extension InstrumentationSystem {
 
 /// Tests that rely on the global InstrumentationSystem
 /// These tests must be isolated from each other since they mutate global state
-@Suite("Global InstrumentationSystem")
+@Suite("Global InstrumentationSystem", .serialized)
 struct GlobalTracingInstrumentationSystemTests {
 
     @Test("Provides access to a tracer")
@@ -67,10 +67,6 @@ struct GlobalTracingInstrumentationSystemTests {
         #expect(InstrumentationSystem._tracer(of: TestTracer.self) === tracer)
         #expect(InstrumentationSystem.tracer is TestTracer)
     }
-}
-
-@Suite("Global Tracing Methods")
-struct GlobalTracingMethodsTests {
 
     @Test("Global tracing methods preserve arguments")
     func globalTracingMethods() async throws {