RFR: 8283597: [REDO] Invalid generic signature for redefined classes

[Alex Menkov]

After pushing fix for JDK-8282241 (https://github.com/openjdk/jdk/pull/7676) random tests from serviceability/jvmti/RedefineClasses start to fail with
java.lang.NoClassDefFoundError: jdk/test/lib/helpers/ClassFileInstaller$Manifest
This is caused by JTReg classpath directories sharing between tests.

Research shown that the issue was caused by using
run compile -g RedefineGenericSignatureTest.java
in the test to include additional debug info.
Actually "-g" it's not needed as the test only needs source file data and it's included by default.

The fix is the same as previous one, the only difference is in the test:
- removed "run compile -g RedefineGenericSignatureTest.java" action;
- removed "-g" option from InMemoryJavaCompiler.compile() call.

@coleenp , @sspitsyn : could you please re-review the fix

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Commit messages:
 - redo gen sig

Changes: https://git.openjdk.java.net/jdk/pull/8007/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8007&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8283597
  Stats: 211 lines in 2 files changed: 201 ins; 7 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8007.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8007/head:pull/8007

PR: https://git.openjdk.java.net/jdk/pull/8007