RFR: 8282852: Debug agent asserts in classTrack_addPreparedClass() [v2]

[Chris Plummer]

> Fix incorrect assert that assumed the debug agent should never see a ClassPrepare event for a class that it already saw when calling GetLoadedClasses. Details can be found in the bug description.

Chris Plummer has updated the pull request incrementally with two additional commits since the last revision:

 - Fix indent.
 - Fix 32-bit builds.

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7752/files
  - new: https://git.openjdk.java.net/jdk/pull/7752/files/6e79c93f..0744dd24

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7752&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7752&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7752.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7752/head:pull/7752

PR: https://git.openjdk.java.net/jdk/pull/7752