RFR: 8350952: Remove some non present files from OPT_SPEED_SRC list

[Matthias Baesken]

JvmFeatures.gmk contains a file list OPT_SPEED_SRC , the list contains files that have to be optimized for speed when the other files are optimized for binary size.
However some non present files are mentioned and should be removed e.g.
genCollectedHeap.cpp
hashtable.cpp
markSweep.cpp
Maybe they were present in old releases.

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Commit messages:
 - JDK-8350952

Changes: https://git.openjdk.org/jdk/pull/23902/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23902&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8350952
  Stats: 3 lines in 1 file changed: 0 ins; 3 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/23902.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23902/head:pull/23902

PR: https://git.openjdk.org/jdk/pull/23902