[jdk17] RFR: 8268366 Incorrect calculation of has_fpu_registers in C1 linear scan [v2]

[Dean Long]

> If there is a mismatch between bytecode use of floating point and generated IR, has_fpu_registers can get an incorrect value and result in a crash or assert.  This PR adds a missing case for the computation of has_fpu_registers, restores an assert that was removed, adds a bailout for non-debug builds, and adds a test.

Dean Long has updated the pull request incrementally with one additional commit since the last revision:

  suggested cleanup

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk17/pull/10/files
  - new: https://git.openjdk.java.net/jdk17/pull/10/files/853d9428..90c8c8f1

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk17&pr=10&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk17&pr=10&range=00-01

  Stats: 20 lines in 1 file changed: 10 ins; 8 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk17/pull/10.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk17 pull/10/head:pull/10

PR: https://git.openjdk.java.net/jdk17/pull/10