RFR: CODETOOLS-7903276: Remove references to ASM from reporting code

[Alexandre Iline]

This is part of the cleanup to allow pluggable instrumentation in JCov.

Once all usages of ASM are within the instrument package, we will have to think of the SPI for the instrumentation plugin.

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Commit messages:
 - CODETOOLS-7903276: Remove references to ASM from reporting code

Changes: https://git.openjdk.org/jcov/pull/21/files
 Webrev: https://webrevs.openjdk.org/?repo=jcov&pr=21&range=00
  Issue: https://bugs.openjdk.org/browse/CODETOOLS-7903276
  Stats: 376 lines in 28 files changed: 214 ins; 30 del; 132 mod
  Patch: https://git.openjdk.org/jcov/pull/21.diff
  Fetch: git fetch https://git.openjdk.org/jcov pull/21/head:pull/21

PR: https://git.openjdk.org/jcov/pull/21