fillChromPeaks: for MS2 chrom peaks: ensure data is integrated from spectra of the correct isolation window

[jorainer]

For gap filling with fillChromPeaks() on MS2 chrom peaks we have to make sure we're filling in data from MS2 spectra of the correct isolation window too. The chromatograms,XcmsExperiment does that already correctly (by considering the "isolationWindow" spectra variable).

Note: this only applies to DIA LC-MS/MS data that uses isolation windows such as SWATH.