test(flaky): skip all performance tests. (aws#6459)

## Problem
aws#6117
aws#6457

These issues keep popping up, regardless of the the thresholds. The
performance tests are causing more problems then they are solving. Real
performance regressions would be captured in telemetry.

## Solution
skip all performance tests, revisit once there is less flakiness. 

---

- Treat all work as PUBLIC. Private `feature/x` branches will not be
squash-merged at release time.
- Your code changes must meet the guidelines in
[CONTRIBUTING.md](https://github.com/aws/aws-toolkit-vscode/blob/master/CONTRIBUTING.md#guidelines).
- License: I confirm that my contribution is made under the terms of the
Apache 2.0 license.

Author: Hweinstock

packages/core/src/shared/performance/performance.ts

@@ -102,8 +102,8 @@ export function performanceTest<TSetup, TExecute>(
     const testOption = options[process.platform as 'linux' | 'darwin' | 'win32']
 
     const totalTestRuns = options.testRuns ?? 10
-
-    return describe(`${name} performance tests`, () => {
+    // TODO: unskip this once flakiness is reduced.
+    return describe.skip(`${name} performance tests`, () => {
         let performanceTracker: PerformanceTracker | undefined
         const testRunMetrics: PerformanceMetrics[] = []