RFR: 8276231: ciReplay: SIGSEGV when replay compiling lambdas

[Dean Long]

To fix the crash, we need to link the class before calling find_cached_constant_at().  I also fixed a confusing "line not properly terminated" error when we fail to load a class.

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

Commit messages:
 - link class so that find_cached_constant_at does not crash

Changes: https://git.openjdk.java.net/jdk/pull/6398/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6398&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8276231
  Stats: 2 lines in 1 file changed: 2 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6398.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6398/head:pull/6398

PR: https://git.openjdk.java.net/jdk/pull/6398