SCB-179 support -(java identifiers) as parameter name with RequestParam

[acsukesh]

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[coveralls]

Coverage decreased (-0.03%) to 87.422% when pulling 57b238d on acsukesh:master into a4720c6 on apache:master.

[liubao68]

Can you please provide a test case for this modification in integration tests? you can refer #482 for examples.

[wujimin]

it's better move the logic to :
io.servicecomb.swagger.generator.core.utils.ClassUtils.correctMethodParameterName(String)

and following code can be optimized:
io.servicecomb.swagger.generator.core.utils.ClassUtils.JAVA_RESERVED_WORDS
io.servicecomb.swagger.generator.core.utils.ClassUtils.correctClassName(String)

[liubao68]

Please fix review comments

[acsukesh]

@wujimin comments fixed. Will add IT and update PR.

[coveralls]

Coverage decreased (-0.04%) to 87.442% when pulling 377fe88 on acsukesh:master into e812ad7 on apache:master.