JIT: Fix alignment insertion assuming only emitForceNewIG can create new IGs

[jakobbotsch]

Issue I noticed over in #73365.
emitNewInstrAlign can create new IGs for other reasons than emitForceNewIG, e.g. if the current IG cannot fit another instrDesc or if we have reached the limit on the number of instructions in the current IG (255).

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Issue Details

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Issue I noticed over in #73365.
emitNewInstrAlign can create new IGs for other reasons than emitForceNewIG, e.g. if the current IG cannot fit another instrDesc or if we have reached the limit on the number of instructions in the current IG (255).

Author:	jakobbotsch
Assignees:	-
Labels:	area-CodeGen-coreclr
Milestone:	-

[jakobbotsch]

I realize there is emitCheckAlignFitInCurIG now, but it does not handle the 255 case (but maybe this is unreachable as we will reach the size limit before?). I'll just close this.