Support double quoted string in MySql and BigQuery dialects

[komukomo]

ref. #439

Support double quoted string for BigQuery and MySQL.

• BigQuery: https://cloud.google.com/bigquery/docs/reference/standard-sql/lexical#string_and_bytes_literals
• MySQL: https://dev.mysql.com/doc/refman/8.0/en/string-literals.html

Below is a test for other dialects.

sqlparser-rs/tests/sqlparser_common.rs

Lines 2917 to 2921 in f29ce10

	fn parse_delimited_identifiers() {
	// check that quoted identifiers in any position remain quoted after serialization
	let select = verified_only_select(
	r#"SELECT "alias"."bar baz", "myfun"(), "simple id" AS "column alias" FROM "a table" AS "alias""#,
	);

[coveralls]

Pull Request Test Coverage Report for Build 2573826050

• 32 of 34 (94.12%) changed or added relevant lines in 4 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.02%) to 89.801%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/parser.rs	1	3	33.33%

Totals
Change from base Build 2535757386:	0.02%
Covered Lines:	8796
Relevant Lines:	9795

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💛 - Coveralls

[alamb]

Looks good to me -- thank you @komukomo