RFR: 8286314: Trampoline not created for far runtime targets outside small CodeCache

[Evgeny Astigeevich]

`relocInfo::runtime_call_type` calls can have targets inside or outside CodeCache. If offsets to the targets are not in range, trampoline calls must be used. Currently trampolines for calls are generated based on the size of CodeCache and the maximum possible branch range. If the size of CodeCache is smaller than the range, no trampoline is generated. This works well if a target is inside CodeCache. It does not work if a target is outside CodeCache and CodeCache size is smaller than the maximum possible branch range.

### Solution
Runtime call sites are always in CodeCache. In case of a target outside small CodeCache, we can find the start of the longest possible branch from CodeCache. Then we check with `reachable_from_branch_at` whether a target is reachable. If not, a trampoline is needed.

### Testing
It is tested with the release and fastdebug builds. Release builds have the maximum possible branch range 128M. Fastdebug builds have it 2M for the purpose of testing trampolines.
Results:
- `gtest`: Passed
- `tier1`: Passed

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Commit messages:
 - 8286314: Trampoline not created for far runtime targets outside small CodeCache

Changes: https://git.openjdk.org/jdk/pull/9235/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9235&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8286314
  Stats: 17 lines in 1 file changed: 15 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/9235.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9235/head:pull/9235

PR: https://git.openjdk.org/jdk/pull/9235