extension/test/integration: skip broken install test for go1.19/1.20

For go 1.19 and 1.20, the extension installs old gopls
https://github.com/golang/tools/tree/master/gopls#supported-go-versions

For #3454

Change-Id: Ia72d3d9a21789404e80da1579d2fd85dfc633883
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/598596
Commit-Queue: Hyang-Ah Hana Kim <hyangah@gmail.com>
Reviewed-by: Hongxiang Jiang <hxjiang@golang.org>
kokoro-CI: kokoro <noreply+kokoro@google.com>

Author: hyangah

extension/test/integration/install.test.ts

@@ -176,7 +176,12 @@ suite('Installation Tests', function () {
 		}
 	}
 
-	test('Install one tool with a local proxy', async () => {
+	test('Install one tool with a local proxy', async function () {
+		// TODO(golang/vscode-go#3454): reenable the test for old go.
+		const systemGoVersion = await getGoVersion();
+		if (systemGoVersion.lt('1.21')) {
+			this.skip();
+		}
 		await runTest(
 			[
 				{