Improve tests of parsers

[gmponos]

before merging #529 if we could merge this first..

[gmponos]

In short description:

• Added more cases to IntlLocalizedDecimalParserTest
  https://github.com/moneyphp/money/pull/586/files#diff-380f41fd51dd5f28ab63197ddc29fe85R116
• Replaces with equals https://github.com/moneyphp/money/pull/586/files#diff-380f41fd51dd5f28ab63197ddc29fe85R57
• Use actual Currency object instead of a Prophecy one: https://github.com/moneyphp/money/pull/586/files#diff-380f41fd51dd5f28ab63197ddc29fe85R23

[sagikazarmark]

Why replace mocks with actual implementations? I mean, I understand the usual reasons, but in this case mocks seem acceptable to me.

[gmponos]

Why replace mocks with actual implementations?

For the usual reasons.. hahaah

• I have seen cases in the past where there were many WTF moments because of mocks... For instance say that it throws an exception although it never does.. for the sake of good programming practices I switched here to actual implementation.
• Although speed is not a problem here.. Prophesize is way heavier.

Let's not make a big deal out of it.. if this is no good I will revert.. no problem.

[sagikazarmark]

Even if we consider replacing mocks with actual implementations, that should be a separate PR, probably covering the whole library.

[gmponos]

Revert the test changes about prophesize :)

[sagikazarmark]

Thanks!