Fix LANG-1834: getReducedFraction throws for reducible Integer.MIN_VALUE numerator

[aakarsh-34]

…LUE numerator

Fixes LANG-1834.

Fraction.getReducedFraction(Integer.MIN_VALUE, -2) previously threw an
ArithmeticException, even though the fraction can be safely reduced to
1073741824/1 before sign normalization.

This adds a special case for when the numerator is Integer.MIN_VALUE and
the denominator is even, mirroring the existing special case already
handled for the denominator.

Added a test verifying the fix.

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[garydgregory]

@aakarsh-34
Don't bother pushing until you have a successful local build. Read the PR template please.

[garydgregory]

Hi @aakarsh-34

Here are some notes based on local testing:

• Test coverage: The new test correctly reproduces the reported bug and checks both result components. It does not cover the full boundary behavior. Add cases for MIN_VALUE/-6, MIN_VALUE/MIN_VALUE, and retained exceptions for MIN_VALUE/-1 and MIN_VALUE/-3. The existing suite already covers MIN_VALUE/2, exercising the new branch with a positive denominator.
• Comment accuracy: The new comment describes a power-of-two denominator, but the condition accepts any even denominator. Prefer: // Halve both operands before sign normalization to avoid negating Integer.MIN_VALUE. The neighboring existing comment has a similar imprecision.
• Test conventions: Rename testMyReducedFractionFix to something descriptive, such as testReducedFactory_minValueNumeratorNegativeEvenDenominator. Match neighboring tests by removing public, inserting a blank line before @Test, and placing it beside the reduced-factory tests.

[garydgregory]

@aakarsh-34 ping 🔔

[garydgregory]

@aakarsh-34 ping 🔔