Remove duplicate test for trace_id

This test asserts if the internal object's `trace_id` is set. This is
tested in the "exposes a traceId" test already.

The description of what the test says it does is covered under the
"creates a Root/ChildSpan with a timestamp" test.

packages/nodejs/src/__tests__/span.test.ts

@@ -52,14 +52,6 @@ describe("RootSpan", () => {
     expect(traceId).toEqual(internal.trace_id)
   })
 
-  it("exposes a start time", () => {
-    const { traceId } = span
-
-    expect(traceId).toBeDefined()
-    expect(internal.trace_id).toBeDefined()
-    expect(traceId).toEqual(internal.trace_id)
-  })
-
   it("creates a new ChildSpan", () => {
     const child = span.child()
 
@@ -142,14 +134,6 @@ describe("ChildSpan", () => {
     expect(traceId).toEqual(internal.trace_id)
   })
 
-  it("exposes a start time", () => {
-    const { traceId } = span
-
-    expect(traceId).toBeDefined()
-    expect(internal.trace_id).toBeDefined()
-    expect(traceId).toEqual(internal.trace_id)
-  })
-
   it("creates a new ChildSpan", () => {
     const child = span.child()