[jdk11u-dev] RFR: 8270196: [11u] [JVMCI] JavaType.toJavaName() returns incorrect type name for lambdas

[Severin Gehwolf]

Please review this partial backport of [JDK-8225810](https://bugs.openjdk.java.net/browse/JDK-8225810) which fixes an issue of returning an incorrect type name for lambda classes. The type name includes a `.` where it should be a `/`. This causes an issue for debuginfo generation in native-image (from Mandrel, which is based on OpenJDK 11u). A regression test for this follows with [JDK-8270184](https://bugs.openjdk.java.net/browse/JDK-8270184).

Backporting the full JVMCI update seems too risky in order to get this simple fix. Thus, the proposal of an OpenJDK 11u specific bug. The change is self-contained to JVMCI.

Testing: test/hotspot/jtreg/compiler/jvmci/ jtreg tests and JVMCI bootstrap test, modified `TestResolvedJavaType.java` from JDK-8270184 (used to fail, now passes).

Thoughts?

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Commit messages:
 - 8270196: [11u] [JVMCI] JavaType.toJavaName() returns incorrect type name for lambdas

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/120/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=120&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8270196
  Stats: 25 lines in 1 file changed: 23 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/120.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/120/head:pull/120

PR: https://git.openjdk.java.net/jdk11u-dev/pull/120