RFR: 8302328: [s390x] Simplify asm_assert definition [v5]

[Amit Kumar]

> This PR cleanups some assert statements and specifies branch condition at calling site itself. Remaining asm_assert methods are inlined as well.

Amit Kumar has updated the pull request incrementally with one additional commit since the last revision:

  illtrap cleanup

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/12822/files
  - new: https://git.openjdk.org/jdk/pull/12822/files/5635d301..a6386679

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12822&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12822&range=03-04

  Stats: 6 lines in 1 file changed: 0 ins; 4 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/12822.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/12822/head:pull/12822

PR: https://git.openjdk.org/jdk/pull/12822