RFR: CODETOOLS-7903277: Remove references to ASM from JREInstr

[Alexandre Iline]

Moving ASM dependencies into the instrument package.
 * There is currently a kind of SPI represented by AbstractUniversalInstrumenter. Whether to keep it or to replace it with something else is a subject for further considerations.
 * Relationship between JREInstr and Instrumentation are not implemented clearly. Addition of fixJavaBase field is yet another hack on top of existing code. This is one of the ways to move forward. The whole JREInstr will need to be refactored anyway with the introduction of ASM agnostic SPI, hence the temporary hack.
 * Should the flag be set in the instrumentation, Instr class now does the work on java.base module. It is also a question for further consideration if other modules are allowed to be modified and what SPI or API would control that.
 * Bunch of JREInstr code commented out as no longer supported since the module system introduction.
 * Module file instrumentation moved to ClassMorph for now. Pending further SPI design.
 * A unit test for JREInstr.
 * Rest of the tests are passing.

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Commit messages:
 - CODETOOLS-7903277: Remove references to ASM from JREInstr

Changes: https://git.openjdk.org/jcov/pull/22/files
 Webrev: https://webrevs.openjdk.org/?repo=jcov&pr=22&range=00
  Issue: https://bugs.openjdk.org/browse/CODETOOLS-7903277
  Stats: 405 lines in 8 files changed: 267 ins; 76 del; 62 mod
  Patch: https://git.openjdk.org/jcov/pull/22.diff
  Fetch: git fetch https://git.openjdk.org/jcov pull/22/head:pull/22

PR: https://git.openjdk.org/jcov/pull/22