Functional tests refactoring (#6559)

## What changed?
1. Refactor functional tests.
2. Move all common code into separate module
3. For every test - create designated test suite.
4. For every test - create '_test.go" file that is executing the
corresponding test suite.
5. Lots of minor refactoring related to code being messy.

tests/acquire_shard.go

@@ -31,11 +31,12 @@ import (
 
 	"go.temporal.io/server/common/log"
 	"go.temporal.io/server/common/log/tag"
+	"go.temporal.io/server/tests/testcore"
 )
 
-// AcquireShardFunctionalSuite is the base test suite for testing acquire shard.
+// AcquireShardFunctionalSuite is the testcore test suite for testing acquire shard.
 type AcquireShardFunctionalSuite struct {
-	FunctionalTestBase
+	testcore.FunctionalTestBase
 	logRecorder *logRecorder
 	logs        chan logRecord
 }
@@ -51,7 +52,7 @@ func (s *AcquireShardFunctionalSuite) SetupSuite() {
 func (s *AcquireShardFunctionalSuite) TearDownSuite() {
 	// we need to wait for all components to start before we can safely tear down
 	time.Sleep(time.Second * 5)
-	s.tearDownSuite()
+	s.FunctionalTestBase.TearDownSuite()
 }
 
 // newLogRecorder creates a new log recorder. It records all the logs to the given channel.
@@ -109,7 +110,7 @@ type OwnershipLostErrorSuite struct {
 // SetupSuite reads the shard ownership lost error fault injection config from the testdata folder.
 func (s *OwnershipLostErrorSuite) SetupSuite() {
 	s.AcquireShardFunctionalSuite.SetupSuite()
-	s.setupSuite("testdata/acquire_shard_ownership_lost_error.yaml")
+	s.FunctionalTestBase.SetupSuite("testdata/acquire_shard_ownership_lost_error.yaml")
 }
 
 // TestDoesNotRetry verifies that we do not retry acquiring the shard when we get an ownership lost error.
@@ -151,7 +152,7 @@ type DeadlineExceededErrorSuite struct {
 // SetupSuite reads the deadline exceeded error targeted fault injection config from the test data folder.
 func (s *DeadlineExceededErrorSuite) SetupSuite() {
 	s.AcquireShardFunctionalSuite.SetupSuite()
-	s.setupSuite("testdata/acquire_shard_deadline_exceeded_error.yaml")
+	s.FunctionalTestBase.SetupSuite("testdata/acquire_shard_deadline_exceeded_error.yaml")
 }
 
 // TestDoesRetry verifies that we do retry acquiring the shard when we get a deadline exceeded error because that should
@@ -193,7 +194,7 @@ type EventualSuccessSuite struct {
 // the next call to return a successful response.
 func (s *EventualSuccessSuite) SetupSuite() {
 	s.AcquireShardFunctionalSuite.SetupSuite()
-	s.setupSuite("testdata/acquire_shard_eventual_success.yaml")
+	s.FunctionalTestBase.SetupSuite("testdata/acquire_shard_eventual_success.yaml")
 }
 
 // TestEventuallySucceeds verifies that we eventually succeed in acquiring the shard when we get a deadline exceeded