The variable generated by IrStatementBuilder.irTemporary doesn't inherit
startOffset and endOffset from the builder. In particular, as a result,
temporary variables generated for elvis operator left operand have
UNDEFINED_OFFSET.
Additionally, ProvisionalFunctionExpressionLowering copies the offsets
of a variable to lowered lambda in the variable initializer. With the
problem described above, this causes invalid debug information in
Kotlin/Native, see KT-49360.
Fix irTemporary by using builder's offsets for the variable.
^KT-49360 Fixed