fix: compare functional option names for indirect calls

[arjun-1]

Summary

Closes Functional Options testing broken for indirect calls #1380. The fix is consists of not comparing the the function names, as it is already asserted when comparing expectedValues and actualValues

Changes

• Adds test Test_Mock_AssertExpectationsFunctionalOptionsTypeIndirectly which would fail without the fix
• Adds test Test_Mock_AssertExpectationsFunctionalOptionsType_Diff to examine behavior of slightly different functional options in expected vs actual.
• Changes the funcName implementation to only compare the relevant last part, if applicable. This aids in reading the diff that is produced when the function names don't. match (for go1.20 or higher)

Motivation

The choice was made to omit the comparison of function names completely, instead of comparing only the relevant last part. The reason is that go1.19 and lower don't give enough any meaningful comparable part in the function name. Nevertheless the most relevant part of the function name is included in the diff result. Without it, the diff yielded in Test_Mock_AssertExpectationsFunctionalOptionsType_Diff would have resulted in (go1.20):

mock.Test_Mock_AssertExpectationsFunctionalOptionsType_Diff.OpNum &{num:0 str:1} != mock.Test_Mock_AssertExpectationsFunctionalOptionsType_Diff.OpNum &{num:1 str:}

The current implementation instead yields a diff:

OpStr &{num:0 str:1} != OpNum &{num:1 str:}

Though there could be added benefit in displaying the full location of the function, I can revert that part if desired.

Related issues

Closes #1380

[arjun-1]

Looks like the approach to compare a relevant part only fails for older Go versions, I'll rethink that
Done

[arjun-1]

Hey @dolmen I believe you were involved in reviewing related change #1381. Anything specific required for this review?

[pmokeev]

@dolmen can you have a look at this PR? I've also encountered the same problem