RFR: 8331027: JDK's ct.sym file packs corrupted module-info classes [v2]

[Jan Lahoda]

> When writing the `ModuleMainClass` attribute, `CreateSymbols` uses an UTF8 entry (incorrect), instead of a Class_info (correct). This patch fixes that.

Jan Lahoda has updated the pull request incrementally with one additional commit since the last revision:

  Removing unnecessary directory cleanup.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/19031/files
  - new: https://git.openjdk.org/jdk/pull/19031/files/bde7257c..369f0bf0

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19031&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19031&range=00-01

  Stats: 2 lines in 1 file changed: 0 ins; 2 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/19031.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19031/head:pull/19031

PR: https://git.openjdk.org/jdk/pull/19031