[MM-62408] Server Code Coverage with Fully Parallel Tests (#30078)

* TestPool

* Store infra

* Store tests updates

* Bump maximum concurrent postgres connections

* More infra

* channels/jobs

* channels/app

* channels/api4

* Protect i18n from concurrent access

* Replace some use of os.Setenv

* Remove debug

* Lint fixes

* Fix more linting

* Fix test

* Remove use of Setenv in drafts tests

* Fix flaky TestWebHubCloseConnOnDBFail

* Fix merge

* [MM-62408] Add CI job to generate test coverage (#30284)

* Add CI job to generate test coverage

* Remove use of Setenv in drafts tests

* Fix flaky TestWebHubCloseConnOnDBFail

* Fix more Setenv usage

* Fix more potential flakyness

* Remove parallelism from flaky test

* Remove conflicting env var

* Fix

* Disable parallelism

* Test atomic covermode

* Disable parallelism

* Enable parallelism

* Add upload coverage step

* Fix codecov.yml

* Add codecov.yml

* Remove redundant workspace field

* Add Parallel() util methods and refactor

* Fix formatting

* More formatting fixes

* Fix reporting

server/channels/store/sqlstore/utils_test.go

@@ -14,6 +14,10 @@ import (
 )
 
 func TestMapStringsToQueryParams(t *testing.T) {
+	if enableFullyParallelTests {
+		t.Parallel()
+	}
+
 	t.Run("one item", func(t *testing.T) {
 		input := []string{"apple"}
 
@@ -37,8 +41,10 @@ func TestMapStringsToQueryParams(t *testing.T) {
 	})
 }
 
-var keys string
-var params map[string]any
+var (
+	keys   string
+	params map[string]any
+)
 
 func BenchmarkMapStringsToQueryParams(b *testing.B) {
 	b.Run("one item", func(b *testing.B) {
@@ -56,6 +62,10 @@ func BenchmarkMapStringsToQueryParams(b *testing.B) {
 }
 
 func TestSanitizeSearchTerm(t *testing.T) {
+	if enableFullyParallelTests {
+		t.Parallel()
+	}
+
 	term := "test"
 	result := sanitizeSearchTerm(term, "\\")
 	require.Equal(t, result, term)
@@ -82,6 +92,10 @@ func TestSanitizeSearchTerm(t *testing.T) {
 }
 
 func TestRemoveNonAlphaNumericUnquotedTerms(t *testing.T) {
+	if enableFullyParallelTests {
+		t.Parallel()
+	}
+
 	const (
 		sep           = " "
 		chineseHello  = "你好"
@@ -109,6 +123,10 @@ func TestRemoveNonAlphaNumericUnquotedTerms(t *testing.T) {
 }
 
 func TestMySQLJSONArgs(t *testing.T) {
+	if enableFullyParallelTests {
+		t.Parallel()
+	}
+
 	tests := []struct {
 		props     map[string]string
 		args      []any