RFR: 8285401: Proxy class initializer should use 3-arg `Class.forName` to avoid unnecessary class initialization

[liach]

Simplify calls `Class.forName(String, boolean, ClassLoader)` instead of `Class.forName(String)`. `make test TEST="jtreg:test/jdk/java/lang/reflect/Proxy"` passes, with the new `LazyInitializationTest` failing the eager initialization check on the baseline and passing with this patch.

On a side note, this might reduce the number of methods that can be encoded in a proxy due to code attribute size restrictions; we probably would address that in another issue, as we never mandated a count of methods that the proxy must be able to implement.

Mandy, would you mind review this?

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Commit messages:
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 - typo
 - 8285401: Proxy class initializer should use 3-arg `Class.forName` to avoid unnecessary class initialization
 - Test for eager initialization

Changes: https://git.openjdk.java.net/jdk/pull/8800/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8800&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8285401
  Stats: 78 lines in 2 files changed: 74 ins; 0 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8800.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8800/head:pull/8800

PR: https://git.openjdk.java.net/jdk/pull/8800