RFR: 8302328: [s390x] Simplify asm_assert definition

[Amit Kumar]

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

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

Commit messages:
 - added inline keyword before function implementation
 - inlined assert method
 - relocation code shortening
 - inline asm_assert
 - update header and cleanup
 - removed asm_assert{ne, high, low}
 - removed asm_assert_eq and asm_assert_static functionality
 - introduce branch conditions

Changes: https://git.openjdk.org/jdk/pull/12822/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12822&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8302328
  Stats: 172 lines in 14 files changed: 50 ins; 79 del; 43 mod
  Patch: https://git.openjdk.org/jdk/pull/12822.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12822/head:pull/12822

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