[perf] Speed up DeadCode rules with cheap guards before type checks, reflection and subtree walks

[TomasVotruba]

Performance refactor of 7 rules. No behavior change - all fixtures pass unchanged.

Each rule ran an expensive op (type resolution, reflection, or a side-effect/node-finder subtree walk) before a cheap check that can bail first:

• RemoveFilterVarOnExactTypeRector - the filter-name membership check now runs before getNativeType(), so a filter_var() call with an unrelated filter constant skips the type lookup.
• RemoveDeadZeroAndOneOperationRector - the literal 0/1 operand check now runs before areNumberType() (two isNumberType() type calls); an operation with no literal zero/one operand can never be dead, so it bails first.
• RemoveParentCallWithoutParentRector - the cheap isAnonymousClass() check now runs before reflectionProvider->hasClass().
• RemoveConditionExactReturnRector - the following-statement Return_ shape check now runs before sideEffectNodeDetector->detect().
• RemoveOverriddenAssignBeforeIfElseRector - the next-statement if/else shape check now runs before matchOverridableAssignVariableName() (which walks for side effects).
• RemoveDoubleAssignRector - the assign-target type check now runs before isSelfReferencing() and the findFirst() side-effect walk.
• RemoveDeadInstanceOfRector - getNativeType() + object-type check now run before resolveClassReflection().

Reordering is safe: all moved checks are side-effect-free bail conditions that must all pass to proceed.