Do a cleanup pass on Core

[pakoito]

As @trevorsummerssmith reported, the behavior of map and flatMap for core constructs was inconsistent inside comprehensions. We'd like for both to be available, at least for the constructs in core.

This PR addresses that to have a more consistent model for inlining: only transformations and getters are inlined.

A second fix removes unnecessary object creation from the implementation of operators. For this, Try.Failure now extends Try<Nothing>

[raulraja]

Great stuff 👏

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@630fa7e). Click here to learn what that means.
The diff coverage is 45.94%.

@@            Coverage Diff            @@
##             master     #971   +/-   ##
=========================================
  Coverage          ?   46.66%           
  Complexity        ?      660           
=========================================
  Files             ?      308           
  Lines             ?     8002           
  Branches          ?      822           
=========================================
  Hits              ?     3734           
  Misses            ?     3939           
  Partials          ?      329

Impacted Files	Coverage Δ	Complexity Δ
...ore/arrow-core/src/main/kotlin/arrow/core/utils.kt	50% <ø> (ø)	0 <0> (?)
...x/src/main/kotlin/arrow/syntax/collections/list.kt	80% <ø> (ø)	0 <0> (?)
...tances-core/src/main/kotlin/arrow/instances/try.kt	65.11% <ø> (ø)	0 <0> (?)
...rc/main/kotlin/arrow/test/generators/Generators.kt	76.31% <0%> (ø)	0 <0> (?)
...s/core/arrow-core/src/main/kotlin/arrow/core/Id.kt	78.57% <100%> (ø)	6 <1> (?)
.../core/arrow-core/src/main/kotlin/arrow/core/Try.kt	64.7% <33.33%> (ø)	22 <5> (?)
...re/arrow-core/src/main/kotlin/arrow/core/Either.kt	44.44% <42.85%> (ø)	8 <2> (?)
...re/arrow-core/src/main/kotlin/arrow/core/Option.kt	62.71% <61.53%> (ø)	22 <15> (?)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 630fa7e...1de09e8. Read the comment docs.