RFR: 8253040 : Remove unused Matcher::regnum_to_fpu_offset()

[John Tortugo]

Relates to: https://bugs.openjdk.java.net/browse/JDK-8253040
Tested on: x86_64 - Linux - Tier1

Remove unused method `Matcher::regnum_to_fpu_offset()` from source base.

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Commit messages:
 - revert adding test files
 - Remove unused method Matcher::regnum_to_fpu_offset

Changes: https://git.openjdk.java.net/jdk/pull/194/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=194&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8253040
  Stats: 33 lines in 7 files changed: 0 ins; 33 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/194.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/194/head:pull/194

PR: https://git.openjdk.java.net/jdk/pull/194