RFR: 8255523: Clean up temporary shared_locs initializations

[Aleksey Shipilev]

See #648. Apparently, LLVM 11 complains that we are computing the number of elements over the array of a different type. Instead of ignoring the warning, it seems better to just clean up that code. We can allocate the whole thing as resource array of the same size. `sizeOf(relocInfo) = 2`, since it carries `unsigned short`.

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Commit messages:
 - 8255523: Clean up temporary shared_locs initializations

Changes: https://git.openjdk.java.net/jdk/pull/897/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=897&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8255523
  Stats: 9 lines in 1 file changed: 4 ins; 0 del; 5 mod
  Patch: https://git.openjdk.java.net/jdk/pull/897.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/897/head:pull/897

PR: https://git.openjdk.java.net/jdk/pull/897