OME-TIFF: close helper readers when working with single-plane files

The reader will be left open if only a tile was read, but if the full
plane from a single plane file is read then the helper reader will be
closed.  This reduces the memory usage for datasets that consist of many
single plane files.

Fixes #12219.
merge dev_5_0 -D org: PR 1172 (Inveon: ignore the absolute path to the image file (rebased onto dev_5_0))
merge dev_5_0 -D org: PR 1180 (Ignore namespaces when filling in an XMLAnnotation's Value (rebased onto dev_5_0))
merge dev_5_0 -D org: PR 1182 (Nikon .nd2 fixes, part 3)
merge dev_5_0 -D org: PR 1183 (OME-TIFF: close helper readers when working with single-plane files)
merge dev_5_0 -D org

Repository: openmicroscopy/bioformats
Updating 623cd6d..715711a
Merged PRs (fast-forward):
  # PR 1146 sbesson 'bfsave: metadata improvements'
  # PR 1179 melissalinkert 'Fix channel count when exporting RGB images in ImageJ (rebased onto dev_5_0)'
  # PR 1167 melissalinkert 'Nikon .nd2 fixes, part 2'
  # PR 1173 melissalinkert 'ImportProcess: remove UI-level exception reporting (rebased onto dev_5_0)'
  # PR 1171 mtbc 'assist #12385: use ArrayList instead of Vector (rebased from develop)'
  # PR 1153 melissalinkert 'CZI: prevent AIOOB exception when populating position metadata'
  # PR 1159 melissalinkert 'First round of Nikon ND2 fixes'
  # PR 1160 joshmoore 'Make private class in DV reader public (see #12358) (rebased onto dev_5_0)'
  # PR 1139 imunro 'Fix for BH .Sdt meas mode 0 & 1 single pixel files & (unrelated) problem with dividing by increment count.'
  # PR 1150 melissalinkert 'Allow dist-matlab to run on Windows (rebased onto dev_5_0)'
  # PR 1157 hflynn 'Removing dead link from Minolta-MRW format page'
  # PR 1144 hflynn 'Updating Zeiss links'
  # PR 1151 hflynn 'Comstat2 link'
  # PR 1134 sbesson 'Add prefix to zip file produced by dist-bftools target'
  # PR 1140 hflynn 'Add 'show and edit on Github' to docs side menu'
  # PR 1143 joshmoore 'Memoizer errs'

Merged PRs:
  # PR 1172 melissalinkert 'Inveon: ignore the absolute path to the image file (rebased onto dev_5_0)'
  # PR 1180 melissalinkert 'Ignore namespaces when filling in an XMLAnnotation's Value (rebased onto dev_5_0)'
  # PR 1182 melissalinkert 'Nikon .nd2 fixes, part 3'
  # PR 1183 melissalinkert 'OME-TIFF: close helper readers when working with single-plane files'

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