Parent issue: #19604

Description

Add Checkstyle checks for all rules under §3.14 - Literals of the OpenJDK Java Style Guidelines v6.

Rules covered

From §3.14 - Literals:

1.long literals should use the upper case letter L suffix - UpperEll
2.Hexadecimal literals should use upper case letters A-F - HexLiteralCase
3.All other numerical prefixes, infixes, and suffixes should use lowercase letters - NumericalPrefixesInfixesSuffixesCharacterCase

Checks to add to openjdk_checks.xml

TreeWalker-level:

<module name="UpperEll"/>
<module name="HexLiteralCase"/>
<module name="NumericalPrefixesInfixesSuffixesCharacterCase"/>