[code-reflection] RFR: Optimize type construction in OpBuilder

[Mourad Abbay]

Further optimize OpBuilder by reducing the overhead of type construction.

-------------

Commit messages:
 - Integrate the changes into OpBuilder
 - Merge branch 'code-reflection' into optimize-type-construction
 - Optimize type construction in OpBuilder

Changes: https://git.openjdk.org/babylon/pull/687/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=687&range=00
  Stats: 120 lines in 1 file changed: 85 ins; 30 del; 5 mod
  Patch: https://git.openjdk.org/babylon/pull/687.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/687/head:pull/687

PR: https://git.openjdk.org/babylon/pull/687