QueryExpressionMap's clone method is missing copying "comment" field

[astritsh]

Issue Description

Expected Behavior

Clone method of QueryExpressionMap should copy everything(all its fields).

Actual Behavior

When clone method is being used from methods like getManyAndCount, count query is missing comment field which wasn't cloned from QueryExpressionMap.
Seems that "comment" field is the last field added in QueryExpressionMap but this field was missed to be added on clone method.

// include the output in code tags like these!
  1.  query: /* a comment */ SELECT "simple"."id" AS "simple_id" FROM "sample" "simple" 

  2.  query: SELECT COUNT(1) AS "cnt" FROM "sample" "simple"                        (missing /* a comment */)

Steps to Reproduce

1. Create a query builder
2. Add a comment there
3. call getManyAndCount

Result:
First main query contains the comment, second query for getting the count does not contain the comment.

this.repository
      .createQueryBuilder()
      .comment("a comment")
      .getManyAndCount();

My Environment

Dependency	Version
Operating System
Node.js version	vX.Y.ZZZ
Typescript version	vX.Y.ZZZ
TypeORM version	v0.2.29

Additional Context

Relevant Database Driver(s)

• aurora-data-api
• aurora-data-api-pg
• better-sqlite3
• cockroachdb
• cordova
• expo
• mongodb
• mysql
• nativescript
• oracle
• [x ] postgres
• react-native
• sap
• sqlite
• sqlite-abstract
• sqljs
• sqlserver

Are you willing to resolve this issue by submitting a Pull Request?

• Yes, I have the time, and I know how to start.
• [ x] Yes, I have the time, but I don't know how to start. I would need guidance.
• No, I don't have the time, although I believe I could do it if I had the time...
• No, I don't have the time and I wouldn't even know how to start.