runtime/coverage: skip more tests in short mode

Add more skips if short mode testing, since some of these tests
still seem to be timing out on smaller and more underpowered
builders.

Updates golang#56197.

Change-Id: I469d9fd3a6be5602243234562fa3fe6263968b56
Reviewed-on: https://go-review.googlesource.com/c/go/+/443376
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: David Chase <[email protected]>
Run-TryBot: Than McIntosh <[email protected]>

Author: thanm

src/runtime/coverage/emitdata_test.go

@@ -22,6 +22,9 @@ import (
 const fixedTestDir = false
 
 func TestCoverageApis(t *testing.T) {
+	if testing.Short() {
+		t.Skipf("skipping test: too long for short mode")
+	}
 	if !goexperiment.CoverageRedesign {
 		t.Skipf("skipping new coverage tests (experiment not enabled)")
 	}
@@ -388,6 +391,9 @@ func testEmitWithCounterClear(t *testing.T, harnessPath string, dir string) {
 }
 
 func TestApisOnNocoverBinary(t *testing.T) {
+	if testing.Short() {
+		t.Skipf("skipping test: too long for short mode")
+	}
 	testenv.MustHaveGoBuild(t)
 	dir := t.TempDir()